Right-hander Brian Schlitter was recalled from Triple-A Iowa.
Grimm had not yet made an appearance this season. He was 5-2 with a 3.78 ERA in 73 relief appearances for the Cubs last season.
''It's been like a nagging kind of thing,'' Cubs manager Joe Maddon said before Friday's game at Colorado. ''It's one of those things I think he thought he could get through, but he eventually got to that point. ... You don't want to take chances with anybody.''
Schlitter was 2-3 with a 4.15 ERA in 61 games for the Cubs last season.