The Chicago Cubs placed second baseman Nico Hoerner on the injured list Friday with a left hamstring strain and recalled utility man Miles Mastrobuoni from Triple-A Iowa.
The IL move is retroactive to Tuesday.
The Cubs also activated left-handed pitcher Brandon Hughes from the 15-day IL and optioned right-hander Javier Assad to Triple-A.
Hoerner, 25, was batting .303 with two home runs and 19 RBIs in 35 games for the Cubs this season after he signed a three-year contract extension during spring training. In five seasons with the Cubs, he is a .