Clay Buchholz had never faced more than 472 batters in a season entering this year. He's up to 523 now and the additional workload seems to be taking a toll on his arm – or rhythm at least.
After maintaining a 36.0% K-rate, 5.47 K/BB, and 0.93 WHIP through his first 116.0 innings (455 batters faced), Buchholz has posted a 17.6% K-rate, 1.5 K/BB, and 1.75 WHIP over his last three starts.
Before we dive in too deep, it's critical to first review a few key pieces of information for context:
1) Buchholz spent his first 116.0 innings between Double-A and Triple-A, while his last three starts have been in the big leagues (1) and Triple-A (2).
2) His last three starts total to just 68 batters faced and 14.1 innings. So how much weight can you put into a mere 13.0% of a pitcher's season anyways?
I'm going to give you my answer to the question above: A LOT.
I use a metric in my rankings that accounts for amateur career (draft position or signing bonus) and age vs. level – you can read more about it here. Upon looking over Buchholz's recent performance, I tried to find some other 23-year-old pitching prospects who are on the cusp of the big leagues to compare him to. But I couldn't find anyone.
Buchholz is actually one of the older pitchers who is in the upper half of my pitching prospect rankings – just three months younger than Kevin Slowey and 11 months younger than Luke Hochevar. Slowey has faced 654 batters this season; Hochevar 609. Big league innings eaters face hundreds more batters than the 523 Buchholz has seen this season – Jeremy Bonderman faced 903 last season.
I have no problem giving young bucks like Clayton Kershaw (500 total batters faced (TBF) to date), Jacob McGee (557), Will Inman (578), and Michael Bowden (551) passes as they tread on to career-high TBF ranges. They are 19.4, 21.0, 20.5, and 20.9, respectively.
As a 23-year-old, Buchholz should have his arm stretched out to the point where he can at least continue to pitch at a level close to he did early in the season. And maybe he's pitching through some kind of injury – if that's the case, I'd definitely cut him some slack. But I'm not going to listen to any converted outfielder arguments. Clay told me that he's always pitched (high school and college).
The Clay Buchholz who has taken the mound dating back to his big league debut (8/17) is not the same Clay Buchholz who had been wowing baseball minds and fans all season. He'll definitely be getting my full attention for the rest of the season, and I'm not ready to start slapping down conclusions. But if he's healthy and he continues to pitch this way, Buchholz will have a very difficult time claiming a top five overall prospect ranking in my book at year's end.
Think I'm getting concerned over normal fatigue? Send an email to adamf@projectprospect.com and let me know your take.