The Chicago Cubs seem to finally be figuring some things out offensively, but their lineup was dealt a serious blow on Sunday as first baseman Anthony Rizzo was forced to leave the team’s game against the Pittsburgh Pirates.

Rizzo, who hit a grand slam in the series opener on Friday, was trying to field a bunt in the third inning when he appeared to roll his ankle:

Rizzo went down to the turf and had to be helped off the field by Jason Heyward and the team’s training staff.

According to the Cubs' PR staff, Rizzo sprained his ankle on the play, but X-rays did not show a fracture. He will undergo an MRI on Monday to determine the severity of the injury, the team said.