Lee suffered the injuries colliding with Rafael Furcal in Wednesday's 5-4 victory over Los Angeles. Lee, 30, signed a five-year, $65 million deal on April 11.
Last year, Lee had a stellar year, hitting .335 with 46 homers and 107 RBIs. This year, he was off to another solid start, hitting .318 with three homers and 10 RBIs in the Cubs' first 14 games.
Lee had never been on the disabled list in his career.
--RHP Ryan Dempster converted his 23rd consecutive save opportunity in Wednesday night's 5-4 victory over Los Angeles to pass Joe Borowski (2003-04) for the all-time franchise lead in that department.
--LHP Will Ohman was on thin ice with his 21.60 ERA in his first 3 1/3 innings of work this year. But he might get a reprieve to turn things around if LHP Scott Eyre (right leg contusion) misses any time in this weekend's series against St. Louis. Ohman would become the only lefty available in the bullpen.
--RHP David Aardsma made his Cubs debut on Wednesday night against Los Angeles and gave up two runs in two-thirds of an inning in a relief appearance thanks in part to surrendering three walks. Cubs manager Dusty Baker has already lamented about the amount of walks his pitching staff is surrendering, and Aardsma could be on a short leash if he continues to struggle with his control.
--LHP Sean Marshall continues to pick up rave reviews for his composure when he is on the mound, but keeping him on the mound is another issue. Through three starts, Marshall has not gone more than five innings in any given appearance, and that's taxing the bullpen.
RHP Kerry Wood (shoulder and knee surgery) hopes to be back by late April.
RHP Wade Miller (shoulder surgery) should be back in May.
RHP Mark Prior (strained shoulder) is throwing on the mound again, but no timetable has been set for his return.
OF Angel Pagan (hamstring, knee) should be back in late May.
1B Derrek Lee (broken right wrist) will be out at least through May.
LHP Scott Eyre (bruised right knee) is day-to-day.