After an examination by team doctor Craig Milhouse, the Angels said Haren has a bruised right forearm. No X-rays were taken, according to the team. Haren will be re-examined Tuesday by team orthopedist Lewis Yocum.
"It's pretty sore, but I don't think it hit bone or anything," Haren said while standing in front of his new locker following the Angels' 6-3 loss to the Red Sox. "It was just the meat of my forearm. They said I was lucky, that it looks like I'll be fine to go next time. It swelled up pretty good, but it's nothing I'm worried about."
Angels manager Mike Scioscia, however, didn't seem so sure about Haren making his next start.
"Sometimes, these things heal quickly," Scioscia said. "It doesn't seem like it got much of the bone. It looks like it was soft tissue, but I'll let Dr. Yocum and the medical staff determine what the extent might be."
After the ball struck him, Haren chased after it, but it wound up as an infield hit. After that, he fell to his knees in pain.
Haren, whom the Angels acquired Sunday for pitcher Joe Saunders, two minor leaguers and a player to be named, left the field Scioscia and trainer Rick Smith. Fans near the Angels' dugout gave him a standing ovation, which he acknowledged with a tip of his cap.
Despite being knocked out early, Haren was upbeat after the game.
"Today was the most relaxing day I've had in a while. Going through the [trade] rumors and stuff was kind of exhausting," Haren said. "It just kind of wore on me and I was just glad it was over, coming here especially. I wish it would have been a better result today, but good things are going to come, I'm sure."
Haren pitched 4 2/3 innings, allowing two runs on seven hits, including an Ortiz home run. He struck out eight batters. The Los Angeles-area native, who began the day second in the NL with 141 strikeouts for the Diamondbacks, struck out everybody in the Boston lineup except Marco Scutaro and Adrian Beltre.
The Red Sox were grateful to hear Haren's injury doesn't appear serious.
"That's not really the way you want to see somebody getting out of the game," said slugger David Ortiz. "That was kind of scary. Every time you see a guy getting hit by a line drive, it seems like everything stops. But he was tough tonight, let me tell you. That first at-bat I had against him, he threw me some nasty pitches."
Mark Saxon covers the Angels for ESPNLosAngeles.com. Information from The Associated Press contributed to this report.