Lee left in the third inning of Thursday night's win over the Washington Nationals with a left flexor pronator strain, an apparent recurrence of the injury that put him on the disabled list in May.
Manager Ryne Sandberg said Friday that Lee will be examined by the team doctor Saturday in Washington, and undergo an MRI and additional tests when the team returns to Philadelphia early next week.
The 35-year-old Lee (4-5, 3.65) missed two months because of a strained left elbow, and was making his third start since coming off the disabled list.
Jimenez, 29, appeared in two games for Philadelphia in June, pitching two scoreless innings. With Lehigh Valley, he was 3-2 with a 1.45 ERA in 38 games, including two starts.