MILWAUKEE -- When Matt Diaz left Milwaukee on Wednesday, he knew there was a good chance that he wasn't going to play baseball for at least another month. His expectations were confirmed by Braves medical personnel in Atlanta on Thursday.

An MRI scan of Diaz's left knee revealed a partial tear of the posterior cruciate ligament. Braves doctors are projecting that the 30-year-old outfielder will miss four to six weeks, meaning there's a chance he may be able to return sometime around the All-Star break.

Diaz suffered the injury on Tuesday, when he slid into an unpadded portion of the wall located in foul territory along the left-field line at Miller Park. He crashed hard into the portion of the wall which included a chain-link fence, causing him to suffer a laceration on his knee that required four stitches.

Diaz played the remainder of the sixth inning before exiting the game after running to first during a bunt attempt in the top of the seventh.

Gregor Blanco, who had been platooning in left field with Diaz, will be given a chance to play on an everyday basis. With Mark Kotsay forced to miss a fourth straight start on Thursday, Blanco was in center field

Kotsay's back has improved in each of the past two days, and there's at least a chance he could return this weekend. However, as long as he's out and not on the disabled list, the Braves will use Omar Infante and Greg Norton in left field.

Diaz hasn't been able to regain the form that allowed him to bat .333 over the past two seasons. He had hit just .172 over his past 23 games, and went on the 15-day disabled list with a .250 batting average.