Jon Lester is headed to the injured list, according to ESPN, after tweaking his left hamstring while running the bases on Monday in the Cubs' home opening win over the Pirates. Chicago manager Joe Maddon told 670 The Score that he expects the left-hander to miss one or two starts and mentioned Tyler Chatwood as a possible rotation replacement.

Lester, 35, reached base on an RBI double in the second inning of the Cubs' 10-0 win. He hurt his hamstring while scoring on a Ben Zobrist single and was pulled in the third after initially trying to stay on the mound. 

Lester downplayed the severity of the ailment on Monday. "Everybody on the training side always kind of thinks of the worst-case scenario, but I don't feel that way," said Lester, who has 14 strikeouts and a 2.57 ERA through 14 innings this season.

 And he was in good spirits about it on Tuesday.

The Cubs are 3-7 to start the season, and their collective 6.70 ERA was the worst mark in MLB entering Tuesday. Lester has been one of the pitching staff's few bright spots, and the Cubs will hope he doesn't miss more than a few starts. If all goes well, Lester could target a return against the Diamondbacks on April 19.