GLENDALE, Ariz. -- The Dodgers are awaiting results of an MRI taken on reliever Tom Koehler's upper right arm and shoulder after his biceps "locked up on him" and forced him from Friday's 7-6 win over the White Sox, manager Dave Roberts said.
"Hopefully it's just something he felt and it's OK, but yeah, we're a little concerned," said Roberts, who was hoping that Koehler, signed as a free agent in December, could pick up relief innings after Brandon Morrow's free-agent departure.
"He's a big part of what we're trying to do. We're counting on him for high-leverage situations, to get righties and lefties. So, to lose him for any extended period of time, that's a big blow."
Koehler started the third inning in relief of starter Clayton Kershaw and allowed a leadoff home run to Adam Engel. He retired one batter, walked two, then threw a ball to Avisail Garcia, after which plate umpire Tony Randazzo motioned to the Dodgers' dugout. Roberts and a trainer came to the mound, and Koehler left the game. He was relieved by Brock Stewart.
Koehler, 31, spent four weeks on the disabled list last year with shoulder bursitis while a starting pitcher with the Marlins. He was traded to Toronto in August and converted to relief, enjoying a renaissance, with a 2.65 ERA in 14 relief appearances and one start.

Roberts said Koehler felt the discomfort on his 12th and final pitch, although he had a very lengthy warmup in the top half of the third inning, when the Dodgers sent 10 batters to the plate and scored four runs.
"Talking to [pitching coach Rick Honeycutt], when it's the biceps, it's usually benign," said Roberts. "He was working through some things in the bullpen the last couple of times and felt really confident. One throw sort of got him a little bit. His velocity was there, but the curveball wasn't."
An injury to Koehler would create a possible opening in the bullpen for Wilmer Font, who is out of options, and Adam Liberatore, who stuck out two batters Friday in his second scoreless inning of the spring. Liberatore is coming off an injury-marred 2017, but Roberts said he so far looks like the 2016 version, which strung together a club-record 28 consecutive scoreless appearances.
"I think Adam's on a mission this year," Roberts said of Liberatore. "After an abbreviated year last year, he looks great, feels strong, is healthy, and the split-change he's featuring is really good."