Chicago Cubs first baseman Anthony Rizzo had to be helped off the field after turning his ankle while fielding a sacrifice bunt.

The team announced that he has a sprained ankle and will undergo an MRI Monday. X-rays did not reveal a fracture.

Rizzo, who is known for charging hard on bunt attempts, broke toward the plate in the top of third inning when Pirates pitcher Trevor Williams squared to bunt. As he neared the ball, Rizzo's foot appeared to dig into the turf and his right ankle turned. He still made the play for the out but then collapsed.

After being tended to by a Cubs trainer and manager Joe Maddon, Rizzo was helped to the dugout, not putting much weight on the right foot. He was replaced at first base by Ian Happ.

The Cubs had been ahead 3-0 after the first inning but promptly gave up the lead after Rizzo went down. Batting leadoff, Rizzo walked in the first inning and came around to score on Kris Bryant's three-run homer.R

Rizzo is batting .289 with 26 homers and a team-high 93 RBIs.

In other moves, the Cubs put shortstop Addison Russell on the seven-day concussion list. He had been hit in the head by a pitch last week and was in the concussion protocol.