Imanaga was diagnosed with a left hamstring strain after being removed from Sunday's game against the Brewers, Maddie Lee of the Chicago Sun-Times reports.
The left-hander suffered the injury during the sixth inning while attempting to cover first base on an attempted double play. Imanaga pitched well prior to the injury and finished with two runs allowed and four strikeouts across 5.2 innings. The severity of the strain isn't yet known, leaving his availability for his next turn through the rotation up in the air.