Indians ace and reigning American League Cy Young Award winner Corey Kluber could lose the rest of the season to a hamstring injury, the Cleveland Plain Dealer has reported.

Kluber, who was scheduled to start Friday night in Detroit, sustained the injury while running in the outfield during the just-completed series in Toronto. He will miss at least one week, but could be done for the year.

The right-hander has been a victim of poor run support in 2015, but has also been a bit more inconsistent than he was in his breakthrough 2014 campaign. If he is indeed finished, he will end the year with an 8-13 record and a 3.41 ERA that is nearly a point higher than what he registered last season.