Tom Wilhelmsen

Crafty Tom Wilhelmsen

By: Jared Ellis

Follow on Twitter: @jarlyjarhead

No one measures my overall performance each day at work and this is completely normal. If I finish less documentation on Thursday than I did on Monday there isn’t someone analyzing my keystrokes to determine that I typed z more often on Thursday and thus that must be the reason I finished less documentation. Or that my coworker spun his chair around to chat an average of two additional times on Thursdays which lends itself to my lack of production. If I have three straight months of work that are less than stellar, chances are likely that only I, and maybe my management, are aware of these struggles. But certainly not journalists or our customers, that’s silliness.

Hey, did you guys hear that Tom Wilhelmsen was terrible with Texas this season?

Wilhelmsen was one of the first causalities of the Jerry Dipoto era, but not necessarily for lack of production. Dipoto wanted to get more athletic and needed a centerfielder, enter Leonys Martin. Dipoto bought low on Martin, which explains having to only get rid of a right handed reliever that wasn’t especially great, but not so bad either. What Texas got was a reliever that wasn’t a closer, but could close in a pinch. He pitched 62 innings in 2015 with an ERA that stood at 3.19 and averaged about a strikeout per inning pitched.

Except Texas didn’t get what they traded for, not even close. A guy that could close if circumstances dictated had become a liability that bounced between Texas’ AAA affiliate Round Rock and the big league team. An ERA in the low threes in 2015 jumped to nearly 11(!) in Texas. His strikeouts per nine was cut in half, et cetera, et cetera.

This post isn’t so much about what Texas got in the trade though, Texas bloggers have probably covered that already. I imagine CAPS were used in addition to many exclamation points. This is more about what Seattle got after Texas, which is pretty much the same thing that he was prior Texas. At least in terms of surface production, but he’s succeeding in different ways.

I would surmise that the SABR-inclined Dipoto was open to trading Wilhelmsen for more than the fact that he needed a starting center fielder, but also that he saw Wilhelmsen beginning a decline. At his best and when he was a closer (2012) Tom was a great strikeout pitcher at nearly 10 K/9. But for the most part he’s hovered around 8 K/9 which is above average and still makes for a functional relief pitcher. But a Tom without strikeouts is a less effective version than himself, he just wasn’t used to getting outs in other ways.

This was part of the problem in Texas, his K/9 cratered, hovering just above four strikeouts per nine. But it wasn’t for lack of throwing strikes, his walk rate remained about the same. He wasn’t getting hit much harder than the season before either. He simply couldn’t end at-bats and enough of those bats ended in hits, sometimes loud ones, that it made an impact.

Fast forward to June 22nd, Wilhelmsen is signed by Seattle after being released by Texas, and makes his first appearance on July 2nd. This time around however, Dipoto and the coaching staff are aware of the pitcher that Tom is today and have a plan to utilize him.

The changes are to his pitch craft, and are multi-layered. For starters he has completely stopped throwing sliders to lefties. And by completely, I mean he hasn’t thrown a single slider to a lefty since he has been with Seattle in 2016. This is in comparison to around 10% of the time when with Texas. He has instead replaced his slider with increased usage of his changeup. I’ll always believe that a pitcher that breathes the same air as Felix will have a better changeup and that is true of Wilhelmsen. He’s not only throwing his changeup more often but has also increased the movement of this pitch since coming over from Texas.

Team Changeup Horizontal Movement (inches)
Rangers -3.57
Mariners -5.57


However, I think the biggest change that’s been made is using different pitch locations to induce weaker contact rather than trying to miss bats. This isn’t a change from Texas either, it’s a change for Wilhelmsen as a whole. He has begun pitching low and outside a lot more than at any point of his career up to this point.

When discovering the link between his current performance and his previous performance, I was reminded of a post covering the Houston Astros that was posted on Grantland. The Astros, in an effort to mitigate pitchers on their staff with low velocity, began pitching on the low outside corner at a rate of 34.8% of the time. Wilhelmsen is pitching in that same area, he’s just doing it a lot more, at around 50% of the time to righties and around 30% of the time for lefties. He’s more than adopted that philosophy of pitch craft, it’s now his practiced religion.

As a result, he’s remained effective despite doing so in a different way. His strikeout numbers are down, but he’s now inducing more soft contact.

Season Team Soft Contact Medium Contact Hard Contact
2015 Mariners 19.40% 60.00% 20.60%
2016 Rangers 17.20% 43.70% 39.10%
2016 Mariners 23.50% 41.20% 35.30%


In addition to inducing more soft contact, the location of most of his pitches also force certain hit types. He’s forcing more hitters to the opposite field than he was than with Texas and also is increasing on the number of groundballs induced. Hitters simply aren’t making great contact.

Season Team Groundball Percentage Line Drive Percentage
2015 Mariners 42.10% 20.50%
2016 Rangers 49.40% 16.50%
2016 Mariners 52.00% 12.00%


Weak contact that is on the ground makes for more outs and for a reliever coming into the game, oftentimes with runners on base already, this is a tangible skill. He may not be the first guy out of the bullpen any longer to get a tough strikeout, but he’s still serviceable.

The consequence of beginning down the path of pitch craft rather than relying solely on physical ability is that the end could be near. The life of a reliever is a combustible one and Wilhelmsen has enjoyed a nice career despite that fact. He also still may have a lot of life left, his fastball still averages 96 and his curve still has a lot of bite. Breathing the same air as Felix doesn’t hurt either when considering his changeup. But if he is done soon, at least some schlub with a blog won’t be exhaustively analyzing his work life.