With the Tigers leading the Red Sox 2-0 with two outs in the top of the fourth inning, Doug Fister came up holding his left side after throwing a ball to Ryan Sweeney. Fister's next pitch was similarly off-target and also signaled Jim Leyland and trainer Kevin Rand, who hustled to the mound to check on Fister.
After a fairly lengthy talk, Fister was removed from the game in favor of Duane Below. FOX announced the injury as being a left side strain, but no other details were immediately available.
Fister was removed from a start during Spring Training with finger soreness, but he never missed any subsequent starts. A left side strain is a different animal, as it's something that could linger and cause further problems.
For what it's worth, Fister did not seem like he wanted to come out of the game, but Rand was doing most of the talking and ultimately Fister exited the game. Hopefully, Leyland and Rand were simply erring on the side of caution rather than allowing the injury to deteriorate over the course of the game.
Fister made it through 3.2 innings, gave up three hits, walked one and struck out three before leaving with the injury. Unfortunately, he won't be in line for a win.