Craig Kimbrel Has an Endurance Problem

Despite his turbulent second half, the White Sox picked up Kimbrel’s $16 million contract option for 2022 before subsequently flipping him to the Dodgers.

Replacing long-time L.A. closer Kenley Jansen, Kimbrel earned the save for the Dodgers on Opening Day. He continued pitching in high-leverage spots over the first few months, and although a few difficult outings inflated his ERA, his underlying numbers were nasty. His 1.95 FIP ranked seventh among qualified relievers during the first half.

Kimbrel actually brought his ERA down in the second half of the season, but nearly all of his other numbers trended in the opposite direction. Most notably, his strikeout rate cratered. He struck out 33.8% of batters he faced in the first half but only 20.7% in the second. He ultimately lost his job as the closer down the stretch and didn’t even make the Dodgers’ NLDS roster.

It’s usually a bad sign when the Dodgers give up on a player, but the Phillies were undeterred by Kimbrel’s second consecutive second-half decline, signing him to a one-year, $10 million pact. The veteran took over closing duties in Philadelphia for the 2023 season.

After a rough first outing, Kimbrel settled in. From April 4 through the All-Star break, he earned 14 saves in 14 chances, pitching to a 2.70 ERA. His strikeouts were back up, and his walk rate was lower than it had been in years.

Kimbrel made his ninth All-Star team that summer. He picked up the save for the National League.

However, almost like clockwork, Kimbrel began to unravel in the second half of the season. He showed signs of fatigue down the stretch as his strikeout rate plummeted and his walk rate rose. Although his 3.09 ERA was still impressive, he collected five losses and blew five saves.

His struggles culminated in two consecutive losses to the Diamondbacks in the NLCS. He gave up the game-winning walk-off run in Game 3. The following night, he let a 5-3 Phillies lead turn into a 6-5 Diamondbacks victory.

One second-half drop-off is nothing to worry about, especially for a player with Kimbrel’s track record. Two consecutive second-half drop-offs might be a little more worrisome. But three in a row? Now that’s a pattern. And patterns are hard to ignore.

Here’s how that pattern looks laid out in a chart:

The troubling pattern is just as visible in the quality of his pitches.

Kimbrel’s stuff has declined in the second half for three consecutive seasons. His velocity has fallen, and both pitch modeling systems at FanGraphs (Stuff+ and PitchingBot) agree his arsenal has been less effective:

So, do the Orioles have a plan to address the elephant in the room? Or, are they just trying to get the most out of Kimbrel while they can?

It’s not as if they were using his arm sparingly. With 13 appearances through his team’s first 27 games, he was on pace for 78 outings this year. Even now, he is still on pace for 68 appearances, a threshold he has only reached three times in his career.

However, it’s worth noting that Kimbrel is throwing with significantly less velocity this year. His four-seam fastball is down to just 93.9 mph (from 95.8 mph last season). For the first time in his career, his fastball velocity is merely average.

That could spell a problem if Kimbrel experiences his typical second-half drop-off in stuff. Alternatively, it could be exactly what helps him stave off the fatigue that has plagued him in recent years. We’ll just have to wait and see how this plays out.

Kimbrel is one of the greatest relievers of his generation, and he is electric to watch when he’s going strong – especially as he and Jansen go back and forth for the active lead in career saves. However, history tells us the dominant version of Kimbrel won’t stick around all season.

Craig Kimbrel ranks among the top 20 pitchers of all time in games finished. He has never made a start. Yet, ironically enough, Kimbrel has no trouble getting off to a good start – his problem is finishing strong.