Meet New Cub Justin Wilson and See What Makes Him So Good

The Cubs’ acquisition of Justin Wilson gives an already healthy bullpen a nice shot in the arm. Striking out over 12 batters per game, Wilson joins a relief corps with an NL second-best 9.91 K/9. You can expect a whiff from this bullpen every third pitch, literally.

Despite an impressive 2.68 ERA, the 29-year-old’s xFIP is 3.47 and his grounder rate of 38.4 percent is far below the ~45 percent league average. Neither is necessarily an issue, though. Willson’s Statcast FIP — which calculates the exact probability of a fly ball going for a homer — of 3.02 reflects that his ERA is the real deal. Even better, his batted ball FIP of 2.02 suggests he’s one of the game’s best relievers.

What makes the new Cubs lefty so good? He throws a four-seam fastball over 96 mph on average and supplements heat with a cutter at 92 and a sharper 85 mph slider. These three pitches have generated a 30 percent whiff rate.

But a recent change finally made it click for the reliever approaching his 30th birthday. As Willson explained to FanGraph’s David Laurila, it was the slider that has helped his career take off this year.

“I wouldn’t classify my cutter as a strikeout pitch,” said Wilson to Laurila. “I will get strikeouts with it here and there, but it’s more of a strike pitch or a ground ball pitch — something to get off the barrel with. The speed change I was looking for by adding a slider would be enough to get more swings and misses. I’ve been throwing it 86ish, and my fastball is 96, and that’s ten MPH. If the hitter is preparing for 96, that should be plenty slow enough to be effective.”

Wilson essentially throws a slider once every ten pitches in between a flurry of four-seams and cutters. All three pitches are released straight over the top. In fact, almost all of his pitches have an ~80 percent more over-the-top release point compared to other lefty relievers, according to PitchFX data.

Theo Epstein and Co. acquired not just one of the game’s best lefties, but one of the best overall relievers. While the trade certainly affects the Cubs’ October chances this year, Wilson also boosts their chances in 2018 and provides an insurance clause if Wade Davis isn’t signed. Enjoy, he’s one of the best.