First-Half Review | Reds Bullpen

by Matt Wilkes — July 14, 2023 in Pitching Analysis

With the All-Star break upon us, we’ve been reviewing how the first half went for the Reds. On Monday, we broke down Cincinnati’s talented position player group that has carried the team to a winning record. Yesterday, we looked at the starting pitchers. Next up is the bullpen!

When we analyzed the pitching staff before spring training, we had a pretty good idea about who would take four of the bullpen spots. The rest, though, was up for grabs. Most of that core is still intact, but the Reds have cycled through numerous relievers at the front-end of the bullpen due to injuries and ineffectiveness. They’ve used 25 different players in relief this season, almost an entire active roster’s worth. Only the Rays and A’s have used more relievers this year (27).

Somehow, the bullpen has held up well. Reds relievers have a collective 3.86 ERA for the season. The peripherals aren’t as strong (4.43 FIP, 4.76 xFIP), but it’s hard to know what to truly make of them given that so many subpar pitchers have thrown relief innings this season. So, let’s look at the core members of the bullpen to get a better sense of how the group has performed.

The Player Charts

As a reminder, here’s what each player’s chart below shows:

(IP) innings pitched
(pERA/pFIP) preseason projected ERA/FIP by FanGraphs
(ERA/FIP) current ERA/FIP
(K%/BB%) current K%/BB%

The players discussed will include relievers on the active roster. We’ll also include highlights (or lowlights) from other relievers we’ve seen this season.

Alexis Díaz

We have to start with the star of the show. Alexis Díaz has become one of the best relievers in baseball, earning his first career All-Star Game appearance. The 26-year-old has converted 26 of 27 save opportunities and fell one save short of matching the longest save streak by a Reds closer to start the season (Rob Dibble, 23). Díaz currently leads Reds pitchers and all MLB relievers in bWAR (2.4). He also leads the Reds in fWAR (1.8) and trails only the Orioles’ Félix Bautista league-wide.

Díaz’s leap forward this year has been fueled by a change in pitch mix. He started throwing more sliders after the All-Star break and now using a near 50-50 split between that and his fastball. It’s made his unicorn fastball pop even more and helped him increase his strikeouts dramatically. Although he hasn’t missed as many bats in recent weeks — possibly due to fatigue — Díaz was carrying a strikeout rate near 50% for much of the first half. He still ranks in the 98th percentile in strikeout rate despite the recent decrease. When you’re striking out that many batters, it makes a 12th-percentile walk rate easier to manage. You can probably recall more than a few instances this season when Díaz has gotten himself into a jam by walking a batter and getting himself right back out of it with a timely punchout.

Noteworthy: Díaz strikes out a lot of batters, but he also forces poor contact quality. His 12.8% popup rate is well above league average (7.1%), and he has also raised his groundball rate by 10 points from last year. While a 41% is still slightly below league average, it has helped Díaz keep the ball in the park. He’s allowed just one home run this season. It’s hard for batters to get hits when they’re pounding the ball straight into the ground or up in the air. Díaz ranks in the 97th percentile in xBA and 98th in xSLG.

Concerns: As mentioned above, Díaz has some lapses in control, although he has brought his walk rate down from last year (12.9% to 11.7%). That may always be a part of his game, but the Reds can live with it if he’s striking out batters at an elite clip and forcing poor contact. Overuse may also be a concern. Díaz is on pace to pitch in 72 games and 71 innings this season, more than he’s ever thrown in a year. His previous high came in 2022, when he pitched 59 games and 63.2 innings. He’s pitched on back-to-back days 10 times this season, more than any other Reds reliever. Only 11 relievers in baseball have pitched on consecutive days more often this year. Although he hasn’t lost any velocity, Díaz has looked gassed at times in recent weeks, carrying a very uncharacteristic 15.8% strikeout rate over his last nine appearances.

Lucas Sims

With Díaz usually reserved for the ninth inning, David Bell has counted on Lucas Sims to carry the Reds through the heart of opposing lineups late in games — often in high-leverage situations. After missing most of 2022 and getting a late start to 2023 with back issues, Sims has returned still spinning the ball as well as ever. The 29-year-old still owns some of the best spin rates in the game, ranking in the 99th percentile with his fastball, slider, and curveball. High spin not only helps him get tremendous movement on all his pitches, but it helps him miss bats at a high clip. Sims ranks in the 89th percentile in strikeout rate and the 96th percentile in whiff rate. His slider, which he’s throwing 50% of the time, has a ridiculous 46.8% whiff rate.

You may be noticing the discrepancy between Sims’ ERA and FIP. That’s largely because of his walk rate. Sims has always been prone to walks (11.1%), but he’s currently issuing free passes at one of the highest rates of his career (5th percentile). A large chunk of Sims’ walks came in May as he was still working his way back into form. He walked 13 batters in 12 appearances from April 30 to May 28. Sims has since sharpened his control, however. Since May 31, he has a 7.4% walk rate in 18.2 innings.

Noteworthy: Groundballs have never been a huge part of Sims’ game, and they aren’t this year either. But like Díaz, he makes up for it by generating weak popups and flyballs. Sims has a fantastic 13.5% popup rate this season, and batters have gotten under the ball 45.9% of the time they put it in play against him (league average is 24.6%). He ranks in the 99th percentile in xBA and the 87th in xSLG.

Concerns: Other than walks, Sims’ biggest concern is his proclivity for giving up flyballs and a low BABIP. He’s been a bit fortunate with a 9.5% homer-to-flyball ratio and .186 BABIP, although forcing a lot of weak popups helps his cause significantly.

Buck Farmer

Buck Farmer has been one of the workhorses in the Reds’ bullpen, pitching in a variety of scenarios and appearing in 42 games. He’s pitched in the fourth inning, and he’s covered the ninth inning on days when Díaz is unavailable. Farmer’s season has been defined by some high highs and low lows, which is pretty typical for a middle reliever. Farmer started the season and ended the first half on rough notes, but he pitched pretty well in between. Tally it all up and he has a perfectly acceptable 3.65 ERA, although the peripherals are less promising (4.29 xERA, 4.57 FIP, 4.64 xFIP).

In the preseason preview, we noted that Farmer had arguably the best season of his career in 2022 thanks to a revamped slider. The pitch has remained nasty in 2023, registering a 43.2% whiff rate and holding hitters to a .151 wOBA (.263 xwOBA). We also pointed to Farmer’s career-high 27.1% strikeout rate as a reason for his success. That, unfortunately, hasn’t carried over as he’s regressed to his below-average career norm. With his strikeouts down, Farmer has had to rely more on his command to get outs this year. On the plus side, Farmer has cut his walk rate from the last two seasons in half, which has taken some sting out of the strikeout decrease.

Noteworthy: There must be something in the water in Cincinnati because Farmer also gets a high popup rate (12.6%).

Concerns: Farmer’s average fastball velocity has dropped by 1 mph from last year, though he has ramped it up as the year moves along. He’s been more prone to flyballs this year — his groundball rate is 10 points under his career average and his flyball rate is up by 10 points — leaving him susceptible to home runs. He’s also due for some regression on his .227 BABIP.

Ian Gibaut

Ian Gibaut has been a staple in middle relief for the Reds this season. Claimed off waivers midway through the 2022 campaign, the right-hander showed some impressive stuff in his three months with the Reds and earned a spot on the 2023 roster. Gibaut has settled into a middle-relief role this season and is tied for Farmer for the most appearances on the team (42). His numbers are a mixed bag. The ERA is strong, but his peripheral numbers scream for regression. Gibaut has a solid 3.86 xERA because doesn’t give up much loud contact, ranking in the 92nd percentile in hard-hit rate.

But his FIP, xFIP, and SIERA are well above 4.00. Why? The biggest factor is Gibaut’s strikeout rate has fallen by 10.5 percentage points from last year. Gibaut had a 30.0% strikeout rate in 2022, which was 33% above league average. This year, he’s 13% below league average. Among pitchers with at least 30 innings in both 2022 and 2023, only two have seen a bigger drop in strikeout rate than Gibaut (Braves reliever Collin McHugh and Astros starter Cristian Javier). Gibaut also walks more batters than the average pitcher, although he’s cut down on his 11.3% walk rate from last season.

Noteworthy: Despite a drop in strikeouts, Gibaut’s whiff and chase rates are higher than last season. Perhaps the strikeouts will come in due time. His fastball can also be a plus pitch when he commands it. He throws in the mid-90s, has excellent extension (90th percentile), and gets a lot of rise on his heater (1.3 inches above average) because his low vertical approach angle prevents it from dropping as much as the average fastball. Gibaut’s four-seamer has a 29.0% whiff rate, which is excellent, and is holding hitters to a .143 average, .302 slugging percentage, and .258 weighted on-base average (wOBA). And guess what? Gibaut also gets a high popup rate (10.4%) thanks to the barrage of high fastballs he throws. Is there an echo in here?

Concerns: Gibaut has mostly had to rely on one pitch, his fastball, to get whiffs. His sweeper isn’t getting swings and misses the way it did last season, with its whiff rate dropping by 10 percentage points and its vertical and horizontal movement decreasing. His sometimes-erratic control and command make him inconsistent, too. Like almost every other Reds reliever, Gibaut is also a flyball pitcher and prone to giving up his share of homers.

Alex Young

For most of the season, Alex Young has served as the sole southpaw in the Cincinnati bullpen. He was signed to a minor-league contract in January, joining Nick Lodolo and Brandon Williamson as former TCU left-handers on the team (Young was also college teammates with Tejay Antone and former Reds southpaw Brandon Finnegan). Young made the Opening Day roster without much competition. Before spring training, we wrote that Young is a groundball pitcher with below-average strikeout and walk rates who relies on command over stuff. He has mostly lived up to that billing.

Young has the highest groundball rate of any active Reds reliever (51.5%), boasting a 90-mph sinker that gets two more inches of drop above average and a changeup with an eye-popping five inches of drop above average. He has a career-high strikeout rate, while his walk rate has fallen by a point from last year. Both are right around league average. Once again, he’s outpitched the fielding-independent metrics (2.52 ERA vs. 3.81 xERA, 4.37 FIP, 4.12 xFIP). Last year, it was because he allowed zero home runs; this year, it’s because of an abnormally high strand rate (87.5%). Regardless, Young is a useful part of the Reds bullpen and has provided solid, if unspectacular, production.

Noteworthy: Despite mediocre strikeout numbers, Young ranks in the 89th percentile in whiff rate and the 97th (!) in chase rate. He’s mixed up his pitch usage with the Reds, featuring his changeup more than any other pitch — probably because it has an outstanding 41.0% whiff rate. Though he’s throwing his curveball significantly less, it also gets a lot of swings and misses (39.4% whiff rate).

Concerns: Can he continue to outpitch his peripherals by almost two runs? Probably not. He’s also been strangely worse against left-handed hitters (.339 wOBA, 4.54 xFIP) than right-handers this season (.284 wOBA, 3.74 xFIP), although that’s more of a small-sample anomaly than an actual, long-term trend.

Derek Law

Entering spring training, Derek Law wasn’t in the forefront of the conversations about the bullpen competition during spring training. But he won a spot and has been a mainstay when healthy. He missed the last week-and-a-half of May and all of June with a right elbow sprain, returning at the beginning of July. Law is yet another Reds reliever outpitching their peripherals by a significant amount. His 2.52 ERA is two runs higher than his FIP/xFIP and three runs higher than his xERA. Law has an above-average groundball rate (46.5%) and doesn’t allow a lot of solid contac, but his strikeout and walk rates are below average. Like Young, he’s been fortunate to have a high strand rate (85.4%).

The 32-year-old keeps hitters on their toes with six different pitches, some more effective than others. Law added a cutter to his repertoire in 2022 and it has become his primary pitch, although it hasn’t gotten great results (.289 BA, .363 xBA, .395 wOBA, .462 xwOBA) and ranks as average by Stuff+ models. It’s possible that his other stuff plays better off a cutter as his primary pitch instead of a four-seam fastball or sinker, however. Law’s slider (42.4% whiff rate), four-seam fastball (34.2%), and curveball (32.0%) have shown promise as putaway pitches.

Noteworthy: Would you believe it if we told you Derek Law has the highest average four-seam fastball velocity among regular Reds relievers this year? Well, it’s true! Aside from Tony Santillan and Ricky Karcher, who’ve thrown 44 combined MLB pitches, Law’s four-seamer has the most zip. Law’s velocity jump started last year, when he gained 1.4 mph from 2021 to 2022 (93.7 to 95.1 mph) and he has tapped into additional velocity this year, averaging 95.6 mph. Also worth noting is that his slider also gets nearly four inches of drop above average.

Concerns: Mostly outlined above. A 12% walk rate is hard to consistently pitch around when the strikeout rate is also below average. Similarly, an 85% strand rate is unsustainable. League average is usually around 72%. Pitchers with high strikeout rates are sometimes better at stranding runners on base, but Law doesn’t fit in that category.

Fernando Cruz

By now, you’ve probably heard about Fernando Cruz’s improbable path to the big leagues (but if you haven’t, here you go). After working away in the minors and various independent leagues for 15 years, Cruz is getting his first extended run at the MLB level. He made the Reds roster out of spring training and has pitched in 27 games, mostly in middle relief.

Unlike many of the relievers we’ve already covered, Cruz’s peripherals paint a sunnier picture of his performance than his ERA. That’s largely because Cruz has struck out nearly one-third of the hitters he’s faced, placing his strikeout rate in the 90th percentile. Cruz is powered by his devastating splitter, which has allowed only three hits this season and generated a ridiculous 55.3% whiff rate — Orioles closer Félix Bautista his the only pitcher who tops that. Cruz has also brought down his walk rate by 2.5 points from last year.

Noteworthy: It’s all about the splitter for Cruz, so how about more notes on it? Opponents are hitting a dismal .064 and slugging .085. The expected metrics back that up, too (.055 xBA, .077 xSLG). Those are truly elite numbers. By Statcast’s run value, it’s tied with Sims’ slider as the second-most valuable individual pitch by a Red (+7 runs value). Only Díaz’s slider has them beat (+14).

Concerns: Cruz’s walk rate is improved but still problematic, ranking in the 13th percentile. When he gets himself into trouble, it’s often because of free passes. Cruz primarily uses his slider and four-seam fastball against right-handed hitters, throwing his splitter only about 27% of the time. Neither the fastball nor slider has been very effective against righties. It could serve him well to use more of his splitter, which has been filthy no matter which batter’s box a hitter stands in (70% whiff rate against righties).

Daniel Duarte

Although Daniel Duarte has only pitched 12 games for the Reds this season, it feels like he’s been around forever given how much turnover the back end of the Reds bullpen has seen. Duarte made the 2022 Opening Day roster but wound up missing most of the season with an elbow injury. After he was non-tendered in the offseason, the Reds re-signed him to a minor-league deal. He worked his way back to the big leagues with a 3.49 ERA, 3.34 FIP, and 4.36 xFIP in 28.1 innings at Triple-A this season.

The 26-year-old throws five different pitches, highlighted by a mid-90s fastball that can touch 97 mph and a slider that gets a whopping 7.4 inches of horizontal movement above average. Duarte has mostly pitched in low-leverage situations with the Reds. While he’s gotten good end results (see the ERA), issuing more walks than strikeouts isn’t the ideal way to sustain that success.

Noteworthy: While last year’s data is limited because Duarte only pitched three big-league games, it appears he’s added both a cutter and a sinker in 2023. Both are flashing on the Stuff+ models and feature strong horizontal movement (4 inches above average for the cutter, 2 above average for the sinker).

Concerns: Pretty straightforward — he’s gotta send those strikeout and walk rates in opposite directions.

Bullpen Roulette

We’ll try to at least mention the other 17 relievers who’ve appeared for the Reds this season. Two of them, Luke Maile and Jason Vosler, were position players. One of them, Ben Lively, is now in the rotation. Only 14 to go! We’ll start with the pitchers who will most likely appear in the second half.

Tony Santillan recently returned from the injured list to appear in a big-league game for the first time in 13 months. He didn’t give up a run in either of his two outings, but he got hit hard and battled with his command. The Reds sent him back to Triple-A prior to the All-Star break to clear a spot for Lively. Santillan will be back in the second half.

Reiver Sanmartin began the season as the other left-handed reliever beside Young. The 27-year-old struggled to replicate his 2022 success as a reliever, struggling mightily with walks (14.3%) before he was ultimately shut down with an elbow injury. As of June 22, Sanmartin hadn’t begun throwing yet, per the Enquirer’s Charlie Goldsmith. Sanmartin is expected back this season, however.

Eduardo Salazar has bounced between the minors and majors a few different times this season. The 25-year-old transitioned from starting to relieving this year and dominated at Double-A Chattanooga, earning a quick call-up to Louisville. The Reds promoted Salazar to the majors after only 4.1 innings in Triple-A. He’s pitched in eight MLB games, but hasn’t quite looked ready for the big leagues, giving up 11 runs and striking out only five in 12.1 innings.

Casey Legumina, acquired from the Twins for Kyle Farmer, has also made his MLB debut this year. His rising fastball shows promise, but his control is erratic (14.3% walk rate). Legumina is currently on the IL with a right shoulder strain.

Alan Busenitz has been called up to the big leagues a couple of times as an emergency reliever, appearing in an MLB game for the first time since 2018. The 32-year-old is still on the 40-man roster, so there’s a chance we’ll see him again in the second half.

Levi Stoudt was used once in long relief, and although he could eventually transition to the bullpen full-time, he remains a starter in Triple-A for now.

Now, onto the relievers who are no longer on the 40-man roster.

Kevin Herget (22.0 IP), Silvino Bracho (7.1 IP), Jake Wong (3.0 IP), Randy Wynne (2.1 IP), Alec Mills (1.0 IP), and Ricky Karcher (1.0 IP) have all been designated for assignment but cleared waivers and remain in the Reds organization at Triple-A.

Luis Cessa (1.0 IP in relief) and Joel Kuhnel (3.1 IP) were also designated for assignment. Cessa was released, signed to a minor-league deal by the Rockies, released again, and signed a minor-league contract with the Nationals recently. Kuhnel was claimed off waivers and traded to the Astros for cash.

Final thoughts — and see you soon?

Given how many relievers the Reds have had to use this season, their bullpen is in a decent spot. The core of the bullpen (Díaz, Sims, Farmer, Gibaut, Young, Law, Cruz) has remained mostly intact all season. It’s not a dominant group — and several members have regression warning signs — but they have two reliable high-leverage arms and a collection of decent middle relievers who are capable of getting outs when they’re in good form. The team has also moved on from many of its weakest links.

Still, an upgrade wouldn’t hurt, especially if the starting rotation continues to struggle. The Reds could get an internal one soon. Tejay Antone, who had his second Tommy John surgery in August 2021 and missed the first half of 2023 due to a flexor strain, has been throwing for some time now and is expected to start a rehab assignment in the near future. Antone, now 29, has missed a lot of time to injury but has flashed dominance when healthy, posting a 2.48 ERA, 3.46 FIP, 3.59 xFIP, and 32.8% strikeout in 69 MLB innings.

Check out our other first-half reviews:

Featured photo by Joe Robbins/Icon Sportswire