There are a range of opinions on how the rest of the season is going to go for the Red Sox, but few would disagree that it’s been extremely frustrating to this point. The offense has been inconsistent at best, and while the rotation has been mostly solid its work been undone by either the lineup or the bullpen far too often. There’s a lot of negativity around this team after they dropped their latest series, a three-game set at home with their two best pitchers throwing against a Rays team that is not too scary. While I think the negativity is a little much, I’d have to be an idiot to not understand where it’s coming from. So, with that in mind, let’s take this morning to focus on one of the positives from the first six weeks of the season: Craig Kimbrel.
The Red Sox closer has been absolutely incredible to start the season. We’re in a period of baseball in which seemingly every team has an elite reliever at their disposal, but after a relatively disappointing first season in Boston, Kimbrel may be throwing better than any other bullpen arm in the game. This isn’t going to be a long post, because the best way to understand how he’s been so good is just to go back and watch some of his outings from this season — including the immaculate inning from earlier in the week — but let’s check out some numbers to help back up how good he’s been.
Let’s start simple: Kimbrel has allowed two earned runs in his 16 2⁄3 innings in 2017, good for a 1.08 ERA. That’s good! He has a FIP of 0.36. That’s good! He has a DRA of 0.86. That’s good! That’s all really good!
Unsurprisingly, he’s been carried by an amazing ability to induce strikeouts. If you are a major-league hitter right now, A) thank you for reading I am flattered and B) you have a better chance of striking out against Kimbrel than doing literally anything else. The Red Sox closer has faced 59 batters this season and 33 of them have been set down by way of the K. That’s a rate of 56 percent, which is unsurprisingly the best among all pitchers with at least ten innings this year.
Looking a little deeper, things only start to get more impressive. According to Baseball Prospectus’ plate discipline numbers, half of the pitches batters have swung at off Kimbrel this season have have gone as whiffs. When they swing at pitches out of the zone, opponents have whiffed a whopping two-thirds of the time. Among the 328 players who have at least 200 pitches on the season, that is the fourth best whiff rate on pitches out of the zone.
What’s more impressive to me, though, is how often he is getting batters to whiff on pitches in the zone. In my opinion, there is no better stat to show how dominant a pitcher is. If you look at this leaderboard for any given season, it is consistently littered with the elite arms in the game. (Case-in-point: Chris Sale leads all starters in this category this season.) This year, opponents are only making contact on 58 percent of Kimbrel’s pitches in the zone. Not only is this the best rate in the league this season, it would be the best ever over a full season since BP started tracking this in 2008.
He’s doing this with the same fastball/curveball combination he’s always had, it’s just reached a different level. It does appear that he has a little more confidence in his curveball this year, as he’s throwing it at the highest rate of his career, per Brooks Baseball. It doesn’t matter what Kimbrel is throwing, though. Both pitches have been out of this world to start the season. Each offering boasts a whiff rate around 25 percent. That isn’t whiff per swing, either. A quarter of the time he throws either pitch, they swing and they miss. For context, Sale’s slider has a whiff rate of 17 percent, and we all know how unfair that pitch is.
The strikeouts are obviously incredible — and somewhat sustainable considering he’s had a full season with a 50 percent strikeout rate before — but what’s really brought him to the next level has been his control. Walks were Kimbrel’s undoing in 2017, and the thought was that if he could get his walk rate down to nine or ten percent he could get back to an elite level. He heard that and decided he’d do you one better. He’s walked just two batters this season for a 3.4 percent walk rate.
It’s not too hard to figure out how Kimbrel is doing this. He’s hitting the zone 55 percent of the time, which would easily be a career high. When he’s missing the zone, batters are chasing at a rate that would be the second highest of his career. It’s really that simple.
There’s a lot to be disappointed with regarding this Red Sox team right now, and most of it is completely fair. One part of the roster that has been more than acceptable is Kimbrel. He’s on another level right now, and while you don’t need the numbers to tell you that if you’ve been watching the games, it doesn’t hurt to gain a little more appreciation for what he’s doing.