Rookie Christopher Morel exited Saturday's game against the Marlins with right hamstring tightness, the Cubs announced.
Manager David Ross pinch hit Nick Madrigal for Morel in the sixth inning, and the Cubs announced in the eighth Morel is considered day-to-day.
Ross said after the game Morel felt tight running the bases and he removed him to be cautious.
"I'm not going to take any risks there," Ross said. "We have plenty of infielders on the bench.
"He's day-to-day. Nothing serious from what I was just told from the trainers, but we'll see how he feels tomorrow."
Morel entered Saturday 0-for-23 in his previous eight games. After grounding out to third base in his first plate appearance, he singled his second trip to the plate to break his hit-less skid.