Tom Wilhelmsen has amazing stuff. He has a 95-97 mph fastball and probably the best curveball of any right hander in the MLB. In 2012 he had an incredible season; 9.87 K/9, 29 saves, and a sparkling 2.50 ERA backed up by a 2.89 Fielder Independent Pitching (FIP) which demonstrated his ERA was no fluke. Out of the bullpen the Bartender was worth 1.9 bWAR and fangraphs.com pegged him as the 10th most valuable closer according to fWAR ahead of big names like Jonathan Papelbon and Rafael Soriano among others. There was little reason to fear a collapse from Tom Wilhelmsen-in fact, I am sure many Mariners' fans felt the second most confidence in him among M's pitchers. I certainly did.
Fast forward to the end of June and Wilhelmsen is no longer Seattle's closer, has blown 26% of his save opportunities, allowed all of his inherited runners to score (2), seen his strikeout percent nose dive (down 7.7%), his walks soar (1.3 more BB/9), and hurt the team according to Win Percentage Added (WPA) at least 7 times. Two of his worst outings came in June. His first, at Minnesota, was a truly epic implosion: he recorded one out while walking three and giving up a triple. According to WPA Wilhelmsen was worth a -91% WPA (at the beginning of the game each team starts out with a 50% of winning according to WPA) that particular outing. His second worst appearance according to WPA, at -76%, was against Houston when he entered the 9th with the M's up one and only managed one out while giving up five runs.
In an effort to determine what has been the issue with Tom causing such a string of poor performances and so many harder hit balls I started to look closely at his stats and actual appearances themselves.
My first thought was to check and see if there were any changes in his repertoire. It turns out Wilhelmsen is throwing 6% fewer curves and he has spiked to slightly over 70% fastballs. That seems like a far too high percentage for his second best offering. However, I made a large graph comparing reliever ERA to percent of fastballs thrown and no trend emerged. Lots of relievers get by with higher percent fastballs than Wilhelmsen. His velocity is the same as in 2012, as are the measures used to rate pitches. So what gives? If his pitches aren't worse and the walks are up but not terrible what is causing Wilhelmsen's struggles? One stat that I think is revealing is his line drive (LD) percent. It is up to 20.4% (from 16%) and teams score 1.26 runs per LD while just .13 runs per fly ball (FB) and .05 runs per groundball (GB).
While a 4% increase in LD% is hardly a spike it did make me ask myself if his location was worse this season. Since his BBs have spiked maybe it is an indication that his command is worse, not just his control. For the sake of simplicity I am going to classify command as locating quality strikes and control as just throwing balls or strikes.
I decided to look at the pitch locations of some of Wilhelmsen's recent bad outings and I did notice more grooved pitches over the heart of the plate when things went wrong. Here is an image I made after Wilhelmsen's bad outing June 21 against the Athletics when Cespedes hit a 2-run HR off him. Josh Donaldson also lined out deep to right field.
The F in a ball stands for fastball, C stands for curveball and Ch stands for changeup. The color code is: red for ball in play, yellow for taken ball, orange for called strike, purple for a swinging strike and pink for a foul ball. The first thing I notice is all the pitches right in the middle of the plate. Even if I hadn't already mentioned it, would you be surprised to know that one of those red fastballs was turned around for a HR? Nobody throws hard enough to get away with that many fastball mistakes when the hitters know it's coming. Wilhelmsen threw 19 pitches and 13 were fastballs. If Josh Reddick weren't such a poor hitter that purple changeup could have been smashed too.
A quick look at Wilhelmsen's full chart of four-seam fastballs (FF) from Texas Leguers makes it look like a trend; Wilhelmson is catching far too much plate with his fastball. Here I added a yellow box for the middle chunk of the plate that pitchers generally want to avoid.
Now I want to show you an image I made from an outing he had recently that was phenomenal to show what a difference location can make for Wilhelmsen. Again, the F ball stands for fastball, C stands for curveball and Ch stands for changeup. The color code is: red for ball in play, yellow for ball, orange for called strike, purple for a swinging strike and pink stands for foul ball.
The difference kind of jumps right out. In this appearance, on June 25th, against the Pirates Wilhelmsen struck out the side, so not only was his location better but the results were better as well. Only one fastball down the middle, and his velocity allowed him to get away with it for a foul ball-and that will happen, but better command is preferable to luck. Also look at all the changeups and curves. He threw 13 pitches and only 3 were fastballs and all of them two-seamers. When I looked to see if maybe he controls that pitch a little better here is what I found:
I think that Wilhelmsen might have better command of this pitch right now-a much smaller percent of his two-seams (FT) end up catching the middle part of the plate. I also think this might be the more effective pitch for him.
To back up that theory a quick trip to Fangraphs.com will show that his two seam induces substantially more ground balls and far less line drives-and that stays true over the course of his career. This season he has also thrown that pitch several tenths of a mile per hour faster than his four seam fastball. The only real reason to prefer the four seam fastball would be that it is much more likely to induce swinging strikes. I think that Tom Wilhelmsen can regain his old effectiveness by featuring a much greater diet of two-seam fastballs (currently approximately a fifth of his fastballs are two seamers) and he can easily make up for the difference in swinging strikes by throwing more curves like in his outing versus the Pirates above. With the problems of Carter Capps and Yoervis Medina being so hittable the Mariners need the Bartender to return to his lights out form of 2012.
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