BOSTON -- Carson Smith served up a home run on Monday night to A's outfielder Khris Davis, then lost his cool when he got back to the dugout, and now the Red Sox have lost their valuable side-winding righty reliever indefinitely.
Smith sustained a right shoulder subluxation when he slammed his glove in the dugout in the eighth inning of Monday's 6-5 loss to Oakland.
The Red Sox placed Smith on the 10-day disabled list prior to Tuesday's game and recalled lefty Bobby Poyner from Triple-A Pawtucket to take his place on the roster.
During a session with reporters, a regretful Smith appeared to be holding back tears at times. The injury will likely keep him out for an extended amount of time.
"It was a frustrating moment, giving up a run in a close ballgame -- that was the first thing that happened," said Smith. "Coming out, throwing my glove out of frustration obviously, my shoulder subluxed during that moment and I definitely regret it."

Red Sox president of baseball operations Dave Dombrowski said it's too early to know if Smith will need surgery.
"He went through extensive testing today, [including an] MRI," said Dombrowski. "They're going to wait a couple of days and let it calm down. I'm sure at some point we'll get a second opinion, but I don't know the severity of it. But it's not mild. We're not expecting him back in 10 days by any means at this point. We'll see how severe it ends up being. It has the potential of being a major injury."
Smith, who had been back to full health this season after undergoing Tommy John surgery in May 2016, had been a key setup man for manager Alex Cora.
"I'm disappointed, just like him," said Cora. "We talked about it last night. We talked about it today. I mean, what can I say? People get frustrated and it's a freak accident, let's be honest. He's not the first guy that slams a glove or throws a bat or punches himself. But it is what it is; we have to move on."
In 18 outings, Smith had a 3.77 ERA. Opponents were hitting .140 against him. In his absence, the Red Sox will rely more on Joe Kelly, Matt Barnes and Richard Hembree.
Tyler Thornburg, who is on a Minor League rehab assignment, could emerge into a high-leverage weapon when he returns. Thornburg missed all of last season with right shoulder woes.
"I think everybody has to do their job," said Cora. "We've got Bobby now. We trust him against lefties and righties. There are a few guys that are throwing the ball well in Triple-A that over the course of the season, they're going to contribute.
"Like I said before the season started, it takes more than the 25 guys that started the season here. Sometimes it takes more than the 40-man roster, you know? So we just have to keep finding the right matchups like we've been doing so far and people have to step up. That's the bottom line."
After missing so much time with his previous injury, this latest development was hard for Smith to stomach.
"Giving up the run was one thing, getting hurt is another," said Smith. "I fought hard to get back to where I was so it's frustrating."
What is Smith's level of concern?
"I'm obviously concerned, any shoulder injury isn't a good injury," said Smith. "Elbow's one thing, shoulder's something you don't want to mess with. I'm concerned."
Given how often Smith throws his glove, he was stunned his shoulder subluxed with that seemingly innocuous motion.
"You can ask Joe Kelly," said Smith. "I throw my glove every day playing catch with him. It's part of my warmup routine, going through my throwing motion, I throw my glove. Actually, I usually hold on to it, sometimes I accidentally release it. I think it was a freak accident. I think fatigue played a factor and my shoulder just couldn't handle it."
Monday's outing was the third time Smith pitched in the last four days.
"I felt like I was hitting my stride, I was pitching well, my slider was getting there, and it's just a freak accident," said Smith. "Just talking to the doctors, I'll follow up with them, see what they have to say."