Caleb Thielbar of the Minnesota Twins has an interesting story. Drafted by the Brewers in the 18th round in 2009, the left-handed reliever washed out pretty quickly, having success in short season ball but washing out in A-ball. A Minnesota native, Thielbar then went the independent ball route, pitching for the St.Paul Saints (as in St.Paul Minnesota) of the American Association. He pitched really well for them in 2011 and then got to finish the year in the Twins system, pitching three games in the Florida State League. In 2012, he jumped all the way to AAA, where he had success. After starting good in AAA, the 26 year old was added to the big league roster. To make the story more interesting, the Twins have let him pitch in 10 games, and he hasn’t given up a run yet. Obviously this pace will not continue, but it might be interesting to look at his Pitch F/X data and see whether its suggests that his quick rise though the minors in his 2nd chance, along with his quick start in the Majors, is a mirage, or predictive of a good MLB future.
Thielbar isn’t going to impress from a stuff standpoint, especially when looking from a fastball velocity standpoint. All his fastballs average 90.3 MPH according to the Brooks Baseball measurement of 55 feet from home plate (rather than the traditional 50). So Thielbar clearly has a below average fastball, and if he is going to succeed, he is going to have to do so by doing something else. Here is a spin and speed chart containing all of his pitches thrown so far (which I used to classify his fastballs, changing a few of the MLBAM tags):
It appears that Thielbar also throws a few changeups, a pretty slow curve, and some sliders it appears. He is clearly very fastball heavy, throwing some kind of fastball (and it appears that he can cut it or sink it) 67% of the time, clearly a healthy percentage (though not extremely high). So despite having a below average velocity fastball, and having success at the big league level so far, he is still a fastball pitcher. The reason for his success doesn’t appear to be movement, at least not according to the Brooks Baseball Leaderboards.
Could average locations give us a better look? I broke up his fastballs in half, because so far this season, he has thrown a pitch over 94 MPH, and another pitch that could still be called a fastball (fitting in perfectly in the Spin and Speed chart) at just over 86 MPH, quite a margin. So I labelled the hard fastballs at 90 MPH and above, with the soft fastballs below 90 MPH. This map is based on my editing of the MLBAM tags.
Clearly, he is doing something differently with his fastballs, mainly, keeping the slower ones lower, working more like a sinker. The more interesting thing is that Thielbar is left-handed, yet his average pitch and fastball is clearly on the glove side of the plate. This is unusual, as only his change is arm side on average (which is standard). This means that he (since he is facing much more righties than lefties, with a worse than league average platoon advantage percentage) is busting righties in with his fastball/all his pitches. Even his curve breaks inside to lefties. You would like to see his slider and change in better locations on average, that is lower, but the change away, fastball in combination against right-handers could be one that works, provided that his hard fastballs aren’t too high. He is putting the pitches he throws over 90 MPH in the high part of the strike zone on average, which could lead to some whiffs and pop-ups, but can also lead to homers. Even Thielbar’s harder fastballs are not thrown that hard. One would think that eventually the lack of big time velocity is going to catch up to him when he keeps trying to bust righties, who will be able to see the ball better against him, inside.
Daniel Schlereth is the best release point comparison for Thielbar. Schlereth isn’t a bad fastball comparison either, though his curve is harder than Thielbar’s. For now, Schlereth’s run in the big leagues was short, but he had a reasonably effective run before regressing and then getting hurt. Schlereth had platoon splits, but not extremely large ones.
So theoretically, and he has done it so far, Thielbar can get righties out at the big league level. Can he continue to do so by challenging hitters with the fastball up and in despite not having plus velocity? This seems to be what determines his success long term. If the aggressive approach works, he could be a valuable bullpen pitcher in the Majors. If not, a rude correction could be coming for Thielbar very soon.