"I'd be shocked if it didn't [result in Tommy John surgery], but we're going to see what Dr. Andrews says," Braves general manager John Coppolella said. "You really feel for the kid because it will be his second [Tommy John surgery]."
Because McKirahan was considered a long shot to gain an Opening Day roster spot with Atlanta, his absence will not have a significant impact on the bullpen battles. But if he Is indeed placed on the 60-day disabled list, the Braves will have yet another 40-man roster spot to give to one of the many non-roster veterans who are fighting for a spot.
The top left-handed bullpen candidates are Ian Krol, non-roster invitee Alex Torres, Matt Marksberry and Rule 5 draft selection Evan Rutckyj. But some of the Braves coaches have said not to count out Hunter Cervenka, another non-roster invitee, who did not allow an earned run over the 16 2/3 innings for Triple-A Gwinnett last year.
"We feel like we still have really good depth there," Coppolella said. "Krol has thrown really well. … Marksberry has been really good in both outings. Just from where we're at, we feel like we have a lot more depth than what we've had not only last year, but really the last two or three years."
McKirahan threw just four pitches before he exited his Grapefruit League season debut on Wednesday with left forearm discomfort. The 26-year-old southpaw previously underwent Tommy John surgery while pitching in the Cubs system in 2012.
The Braves acquired McKirahan from the Marlins during the final week of last year's Spring Training with the understanding that in order to keep control of him, they would need to carry him on their active roster throughout the regular season because he'd been selected during the 2014 Rule 5 Draft.
Less than two weeks into last year's season, McKirahan received an 80-game suspension for testing positive for Ipamorelin, a performance-enhancing substance, in violation of Major League Baseball's Joint Drug Prevention and Treatment Program. He returned in July and ended up posting a 5.93 ERA over 27 appearances for Atlanta.
Mark Bowman is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.