OAKLAND -- The pitching-depleted A's watched another of their own succumb to injury on Monday, when rookie left-hander Sean Manaea was forced to leave his start against the Rangers with a strained pronator muscle in his forearm.
The injury is believed to be minor based on an initial examination by the team doctor during Oakland's 14-5 victory, but the A's will have a better indication of his status following an MRI on Tuesday.
Even if Manaea is forced to go on the DL -- in which case right-hander Jesse Hahn would likely be recalled from Triple-A Nashville -- he's mostly relieved he's avoided "the TJ word," he said, referring to the Tommy John procedure.
"My first thought was [that] it's pretty scary, just because you hear about forearm stuff all the time and TJ," Manaea said. "That word, I try not to think about it. But from what they told me, it's nothing too serious."
"First thing you think about, obviously, in that area is something bad with the ligament, but from what I'm told, it's muscular in nature," manager Bob Melvin said. "So we'll see how he feels tomorrow."
Manaea pitched to two batters in the fifth inning, allowing a one-out homer to Shin-Soo Choo before drawing a visit from Melvin and a trainer. Manaea was seen pointing to his forearm as he exited, with left-hander Daniel Coulombe entering in relief.
Data shows that Manaea's fastball, regularly in the low to mid-90s, topped out at 90 mph in his final inning, averaging 87 mph.
"I saw it real early in the inning. The velocity dropped," Melvin said. "At some point, when you're trying to distinguish the changeup speed and his fastball, then it's time to go out there and check."
Manaea said he felt tightness in the area, akin to what he experienced on a lesser scale while pitching for Triple-A Nashville earlier this season and again following a bullpen session in Cincinnati over the weekend. He deemed his early exit "precautionary."
"I'm feeling not too bad," Manaea said. "It's happened before, and it could be a couple days or a couple weeks. That's good news for me. I'm just hoping it's not anything worse than that."
Manaea is 2-4 with a 6.02 ERA through the first nine starts of his big league career.
Jane Lee has covered the A's for MLB.com since 2010. Read her blog, Major Lee-ague, and follow her on Twitter @JaneMLB. This story was not subject to the approval of Major League Baseball or its clubs.