Alex Wilson was the backbone of the Tigers’ bullpen again

The Tigers have gone through a lot of changes during Alex Wilson’s tenure in Detroit. When he came over from the Boston Red Sox in the Yoenis Cespedes trade after the 2014 season, he no doubt viewed it as a lateral move to another perennial contender. It hasn’t worked out that way, but Wilson is one of the few who doesn’t bear any blame. For four seasons he’s been a gritty source of stability in a typically erratic bullpen. Things were no different in 2018.

Wilson tossed 61 ¹⁄₃ innings for the Tigers this season, and once again surpassed the expectations of his peripheral numbers. A 3.36 ERA was actually the second worst of his tenure, but still extremely welcome. So was his versatility. The Tigers went so far as to allow him to moonlight as a starting pitcher in spring training. Wilson then proceeded to handle his typically diverse array of roles throughout the year in typically unflappable style.

There just aren’t a lot of relievers like Alex Wilson, especially in this strikeout driven era. Most metrics still look at his success as smoke and mirrors to a degree. The fielding independent numbers say he shouldn’t be this effective, but he manages anyway. Every year Wilson seems to define grit or insanity by trying to pitch on a fractured leg, or by tearing his plantar fascia entirely in his left foot and returning without a hitch a few weeks later. Apart from that time he shaved his beard, he’s been relentlessly solid.

We’re now four years into his term with the Tigers, and Wilson has tossed 264 ²⁄₃ innings, with a 3.30 ERA. Scoff at his career 16.3 percent strikeout rate all you want, or his career 3.81 FIP. Normally we’d agree, but the guy gets outs. Does it still feel like he could just crumble into ineffectiveness at any point, because his margin for error is slender? Yeah maybe just a little bit.

One big stat: 53.5 percent slider usage

The standout factor in a solid 2018 season for Alex Wilson, was his transition to pitching backwards. He dropped his fastball usage drastically to 41.8 percent. His previous low in four seasons with the Tigers was 54.7 percent fastballs. In place of his sinker and fourseamer, Wilson turned to his slider in a major way, and used it to produce a groundball rate of 49.2 percent, his highest mark since the 2015 season. It was otherwise a quintessential Alex Wilson season, as he maintained his typically excellent walk rate, kept hitters on the ground and in the park, and seemingly had the ball bounce his way, as witnessed by his .237 BABIP against.

The slider averaged 86.3 mph and hitters batted just .188 against it. Statcast’s expected batting average (xBA) was still just .219, and considers factors like exit velocity and launch angle off the bat. He routinely buried the pitch glove side, down and just off the plate, to hitters of either hand. While the whiffs were typically hard to come by—stories about Wilson trying to re-shape his cutter-ish slider into more of a swing and miss pitch are a spring staple at this point—he managed to dominate with weak contact anyway. Take a look at hitters spray chart against the slider.

Hitters struggled mightily to pull the breaking ball. It’s not a particularly notable pitch for movement or velocity, but Wilson pounded the corners with it, especially down and away to right-handed hitters. It’s a very elemental approach. Wilson swings his sinkers at 92 mph back over the outer edge, and then follows up with sliders breaking the other way out of the same eyeline. He’ll pump a fourseam fastball up and in to keep a hitter honest, particularly against lefties, but that’s just about his entire repertoire. He just has the guile and command to survive out there with a very limited arsenal.

That lone home run to left you see on his spray chart came courtesty of Adam Engel of the White Sox on August 13. Otherwise, most hard contact in the air went to center and right field, where presumably JaCoby Jones, Leonys Martin, or Nicholas Castellanos sometimes, hauled them in. His spray chart with the slider seems to have fit Comerica Park like a glove. That’s not the kind of thing you can bank on going forward, but it helped him to limit opposing hitters to a meager .094 ISO against the slider, despite him throwing the pitch over 50 percent of the time.

There are a lot of oddities with Alex Wilson’s season. He pitched like a specialist against right-handers in a reversal of the year before. He struck out a respectable number of left-handed hitters, but they crushed his fastball for a .356 ISO against. Against right-handers in 2018, Wilson struck out a truly dreadful 14.8 percent of hitters, and yet completely suppressed their production against him by getting a lot of weak contact. The average exit velocity of balls put in play off of Wilson by right-handed hitters was just 84.7 percent. That’s well below the league average of 87.7 mph.

What I’m trying to tell you is that Alex Wilson’s numbers are just weird and it feels like literally any outcome is possible next season. He continues to allow a scary amount of balls in play, but balances that with better than average walk and home run rates. He didn’t enter into so many high leverage spots, but as he has year after year, Wilson provided a steadying presence to the Tigers’ bullpen.

The problem with Alex Wilson, is that teams just don’t trust a guy who lives on weak contact and low walk rates. At a point in the Tigers rebuild when trade chips are key, Wilson just doesn’t seem likely to draw much interest as he heads into his age 32 season. No doubt the Tigers would’ve been willing to deal him had anyone come calling in the past year. There’s value in his versatility and professionalism, but he just won’t ever possess the kind of wipeout breaking ball and power heater that teams are looking to stock in their bullpen.

In the end Tigers may be better off allocating Wilson’s roster spot, and projected $2.8 million in arbitration, to someone else, even if they can’t really get much in return. With numerous roster decisions to make, and players to protect from the Rule 5 draft, they may decide to cut the veteran reliever loose. On the other, it may be that Wilson is just more valuable to the Tigers than anyone else, and one can imagine Ron Gardenhire agreeing with that assessment.