Oakland A’s starter Sean Manaea exits game with left pronator (forearm) muscle strain

Oakland Athletics starting pitcher Sean Manaea exited Monday’s contest against the Texas Rangers after 86 pitches with what the A’s have called a “left pronator muscle strain” (via Joe Stiglich, CSN), which is in the forearm. Manaea was pointing at his forearm as he left under a trainer’s escort, and his fastball velocity dipped significantly in that inning. More information may be available after tonight’s contest.

A pronator strain can be a warning sign of underlying damage to the ulnar collateral ligament or it could be nothing, says Dr. David Geier, an orthopaedic surgeon and sports medicine specialist from Charleston, South Carolina in an interview with Athletics Nation in 2014:

AN: Whenever you hear the words "going to visit Dr. James Andrews," you pretty much know that's the code for "he's having Tommy John next week." Is there one thing in particular that, more often than the others, makes you think, "oh, that guy's going in soon"?

DG: Well, a lot of times what you're hearing reported from the media is somewhat due to lack of translation. But when you hear "forearm tightness" or even the more formal injury, flexor pronator strain, which is a strain of the muscles right over that ligament, at least it makes you worry that there may be underlying damage. Is it truly that the muscle is just tight like you say and is just inflamed or is there some sort of structural damage to the elbow under it that's causing that muscle to work too hard? If you go back and look at all the press releases of Stephen Strasburg in the week before he went down, he was out for a start due to a flexor pronator strain and then shortly thereafter he went down with the Tommy John injury. Those would be words that would at least concern me, but there are pitchers who get flexor pronator strains and do fine. But any kind of medial (inside) elbow pain is worth looking at closely and being very careful with.

If Manaea cannot make his next start, the A’s will need a starter for Saturday’s contest against the Los Angeles Angels. The A’s are already calling up Eric Surkamp to start in place of Rich Hill for Tuesday’s game against the Rangers. Jesse Hahn was recently demoted to Triple-A Nashville to allow Daniel Mengden to be called up, but Hahn could be recalled to directly replace Manaea if he goes on the disabled list.