DETROIT -- Max Scherzer left his start Tuesday night after only two innings because of a fatigued right shoulder, a potentially damaging blow to the Detroit Tigers as they try to catch the Chicago White Sox for the AL Central title.

An MRI on Scherzer's shoulder revealed no structural damage. He's expected to go a couple days without throwing, then be evaluated again.

"I didn't have any pain in my shoulder -- it was just like my arm was dead," Scherzer said. "MRI came back negative. All the structural -- it's all good."

Scherzer left after allowing a run and two hits Tuesday against the Oakland Athletics. He struck out four and threw only 44 pitches before left-hander Darin Downs came on from the bullpen to start the third inning.

Downs (2-1) pitched 2 2/3 scoreless innings for the 12-2 win. Despite the victory, the Tigers still trail the White Sox by three games in the division.

Scherzer has been terrific for the Tigers down the stretch, legitimately challenging Justin Verlander's status as the team's most effective pitcher. Scherzer entered the game with a 16-6 record and a 3.77 ERA, as well as a major league-leading 220 strikeouts.

That was after the right-hander's ERA was an unsightly 5.88 in early June.

If Scherzer is sidelined, it could mean a return to the rotation for rookie Drew Smyly. The left-hander is 4-3 with a 4.25 ERA but hasn't been needed to make a start because the Tigers traded for Anibal Sanchez at the deadline.

Information from The Associated Press was used in this report.