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Tom Wilhelmsen Thrives With Fastball

Tom Wilhelmsen converted his seventh save of the season Monday night against the Orioles, tossing a scoreless ninth inning. The appearance marked his 16th straight without allowing an earned run, a span encompassing 19.2 innings pitched.

Wilhelmsen brandishes a three-pitch arsenal, using a curve and change along with his fastball. But it’s the fastball — averaging 95.8 MPH, 14th fastest among relievers — that defines his success.

Wilhelmsen is striking out 10.9 batters per nine innings this year. In order to get to two strike counts, Wilhelmsen has been exceptional at generating strikes without allowing the batter to put the ball in the play — not just swinging strikes, but also called strikes and foul balls. His fastball comprises over two-thirds of his pitches, and he’s able to use it to great effect to get to two-strike counts. Although he only generates 7.9% swinging strikes in zero or one-strike counts (still great for a fastball), Wilhelmsen is able to keep the ball out of play while racking up strikes:

Over 50% of his fastballs with less than two strikes have gone for strikes not in play — 24% called strikes, 20% fouls, and 8% swinging strikes. This is what allows Wilhelmsen to get to so many two strike counts, and that’s where his fastball gets especially dangerous:

In 74 fastballs thrown in two-strike counts, Wilhelmsen has drawn just as many swinging strikes (18) as he’s thrown balls, an absurd 25.7% rate. He’s painted another three for called strikes, and he’s given up just two hits next to 14 outs in play. Particularly since Wilhelmsen’s scoreless streak has started, it’s not as if hitters are chasing out of the zone, either:

Only one of these swinging strikes is clearly out of the zone, and then only by about six inches.

Wilhelmsen, known simply as “Bartender” to some, is now beyond just a guy with a great story who made it to the major leagues. His fastball is one of the best in the game today and behind it, Wilhelmsen is becoming one of the game’s elite relievers.

Graphics made with Tableau Public. PITCHf/x data from joelefkowitz.com.