The Rays Bullpen Has Been Surprisingly Poor

Remember early in the year, when the Rays were winning seemingly every single game? Well, they still are. They’re not on the 130-win pace they were at the beginning of May, but the fact they’re still well ahead of anyone else in a loaded division is impressive in itself. So how are they winning so much? First off, they put runs on the scoreboard like no other.

If the season ended today, their 127 wRC+ would be the highest in MLB history, ahead of the Big Red Machine, murderer’s row Yankees, or recent Astros squads. We’ve written about players like Randy Arozarena, Wander Franco, and Yandy Díaz, who have all put up superstar performances. And despite losing both Drew Rasmussen and Jeffrey Springs to injury, Tampa’s rotation grades out impressively thanks to free-agent signee Zach Eflin having a career year, top prospect Taj Bradley putting up good numbers, and Shane McClanahan continuing to do Shane McClanahan things.

Finally, there’s the bullpen. For the past decade, much of the Rays’ reputation as a premier organization for player development has come from their ability to turn almost anyone into an above-average reliever, building competitive playoff pitching staffs with minimal contributions from the starting rotation. With two key rotation pieces shelved for the season, the relievers must be neutralizing opponents at an elite rate. Let’s see how their season is going.

As surprising as it is, the Rays’ 4.54 bullpen FIP ranks sixth worst in baseball, narrowly avoiding sub-replacement level status. How has the team with the greatest track record of reliever development experienced such futility this season, and how have they won so much despite leading the league in bullpen innings?

It should first be noted that while the Rays’ bullpen is near the bottom of the barrel in terms of FIP, they rank a perfectly average 15th by ERA. As a group, they’ve outperformed their FIP by 0.60 runs, a mark beat only by the Padres, Guardians, and Yankees, who make up the top three in reliever ERA. The Rays’ defense does a tremendous job of converting balls in play into outs; thanks to having the second-best team DRS from non-framing components, the bullpen has allowed a BABIP of just .262. Much of their FIP overperformance has come from the main bulk arms who have stepped in after the injuries of Rasmussen and Springs; the likes of Josh Fleming and Yonny Chirinos have been great in the ERA department despite strikeout and walk numbers that look like they’re from 1923 rather than 2023.

It’s pretty clear why these names have been paired with openers: their peripherals indicate their stellar run prevention is unlikely to continue for long. In fact, Fleming’s last appearance was a full-length start where he surrendered five homers, tied for the most allowed by any pitcher all year, before he went on the IL. If (and perhaps when) these bulk relievers’ performances fall back to earth, this bullpen’s numbers could become even worse. But much of their struggles has come from regressions in the efficacy of the short-burst relievers who returned from last season’s roster. Nearly every returner has experienced some worsening in performance:

While many of these pitchers’ results still look great on the surface, their underlying numbers, especially in the strikeout and walk departments, have sharply declined. Despite dominating the fastball vertical movement leaderboard, Poche’s strikeout rate has been cut in half from his 2019 season. His 2.36 ERA is aided by a miniscule .228 BABIP and 4.8% HR/FB rate. Adam has been thrust into more high-leverage situations with Fairbanks injured for much of the season, but his fastball has lost a tick of velocity. As a result, hitters have slugged .645 against it, compared to just .298 last season. Perhaps more concerning has been an increase in walks. It’s easy to see why: his chase rate has fallen from the 96th percentile in 2022 to the 44th this year. The biggest source of his drop in chases has come from his reworked sweeper. Compared to last season, Adam has sacrificed 2.6 mph of velocity to add eight inches of horizontal break; his 21.1 inches of movement now trails only Rich Hill. But that much movement without any other glove-side pitch hasn’t been fooling batters, as they’ve been able to lay off them quite well. The sweeper still has earns great results on contact, but it can also put him in hitter’s counts where he throws more fastballs, which have been getting crushed.

For some pitchers, their struggles have gotten them off the roster entirely, with Beeks and Thompson both being sent down to Triple-A. The former has simultaneously experienced strike-throwing issues (his 52.9% first-pitch strike rate lands in just the fourth percentile) and a worse SLGcon on both his fastball and changeup, and was optioned with a 5.82 ERA after posting a sub-3 mark from 2020 to ’22. Selected to the big league roster in his place was Zack Littell, who hasn’t fared any better in his limited body of work. Each of the six main returners from last season’s bullpen had a strikeout rate above the league average for relievers, but through nearly half of this season, all have fallen below average besides Adam.

While the holdovers from last season’s bullpen haven’t pitched to expectation, there are a few new faces that have stabilized the group considerably. Kevin Kelly was a Rule 5 pick by the Rockies who was immediately traded to Tampa Bay for cash considerations and leads the staff in relief innings pitched so far. On the opposite side of the service time spectrum is the 36-year old Jake Diekman, who was claimed off waivers from the White Sox. While both had rocky starts, neither has allowed a run in the past three weeks and each has an ERA below 3.40. Robert Stephenson, recently traded from Pittsburgh, has also been a welcome addition. His career performance thus far has been up and down; he was one of few relievers to conquer Coors Field in 2021, but also had an ERA north of five last year and has a career FIP- of 109. The Rays clearly had faith in the pitch data on his slider, which he throws over half the time. It’s generated whiffs on over 40% of swings throughout his career and has earned a plus stuff grade from PitchingBot (as have the breaking balls of both Kelly and Diekman). Stephenson has allowed just one run in seven appearances on his new team.

Both Kelly and Diekman fit the mold the Rays target in reliever acquisitions: unique arm angles and release points. In 2020, Mike Petriello observed that the relievers they used in the playoffs fired from wildly different release points, preventing the opposing Astros from getting used to any type of delivery. The current squad has three sidearm pitchers in Kelly, Diekman, and Thompson; others like Fairbanks and Beeks throw over the top, generating plus carry on their four-seam fastballs. And while low-slot pitchers are often vulnerable to opposite-handed hitters, none of their three sidearmers have an exaggerated platoon split; in fact, Thompson has dominated lefties even more than fellow righties throughout his career.

The Rays of the past five years have been defined by elite pitching, especially in the relief and swingman types, with just enough offense to not be an outlier compared to other playoff teams. This year, the script has been flipped. Despite running it back with most of the same hitters as the 2022 squad (that had a collective 101 wRC+), their typical lineup features seven hitters with a wRC+ of 130 or higher. They’ve scored seven or more runs in 30 games so far, just two shy of their 2022 total. It also doesn’t hurt that their rotation has a league-leading 3.11 ERA and leads the AL in fastball velocity. The reason to be worried about the bullpen on a team with such modernized pitching usage like the Rays is simple: the more relievers you use per game, the higher the chance that one of them does poorly. But Tampa Bay has shown that even with an uncharacteristically shaky relief group, piling the runs on at a historic rate will work just as well.