Cubs' Jon Lester: MRI scheduled for Tuesday

Lester will undergo an MRI on his left hamstring Tuesday, Jesse Rogers of ESPN.com reports.

Lester was forced to leave Monday's start against the Pirates in the third inning due to the injury, which he appeared to suffer while running the bases. The length of his absence won't become clear until the results of the tests are known, but he's expected to miss at least one start, Sahadev Sharma of The Athletic reports.