Curveball Data Offers Optimism for Craig Kimbrel’s Future

Despite the barrage of home runs being hit against him, there is a reason to be optimistic about Craig Kimbrel‘s 2020 season. You wouldn’t know it from the fastballs he grooved en route to a 6.53 ERA last season, but his knuckle curveball spin rate gradually increased as 2019 progressed.

Kimbrel’s breaking ball made him one of the game’s elite closers and helped turn Yu Darvish back into the ace the Cubs needed him to be. Darvish didn’t actually get to see Kimbrel’s best curve, which may have come at the end of the 2018 season. By August and September of that year, the closer was spinning curves around 2700 RPM, nearly a 10% increase from his 2500 RPM rate in April and May.

Kimbrel’s spin rate was following the same relative trajectory in 2019, starting out around 2500 RPM in June and gradually increasing on an outing-by-outing basis. Unfortunately, injuries derailed his progress and time simply ran out for him.

Granted, this data can also be interpreted in discouraging fashion. After all, if Kimbrel’s performance follows the same trend in 2020, time will run out on him once again. But there are some differences from last season that should prove helpful in recovering his old form.

Not only is Kimbrel entering his second year with pitching coach Tommy Hottovy, but he had been equipped with high-tech resources prior to starting the season. For instance, he recently discussed how his shutdown training included a Rapsodo device that he used to work on his changeup. Though he’s almost never thrown the pitch in live games, it’s been part of his BP arsenal for a while and could help to offset the decrease in fastball velocity.

As ugly as the results were, it’s not as if Kimbrel was that off in 2019. His curveball spin rate was well within the range of his 2018 early-season games, as was his strikeout rate, he just didn’t have enough runway to get off the ground.

Provided it doesn’t take him several weeks to find his groove, increased familiarity with the coaching staff and team, not to mention the potential for a new pitch, should have Kimbrel throwing much better.