Milwaukee — The Braves put outfielder Matt Diaz on the disabled list after Tuesday night's game against the Brewers, in which he crashed into the wall in left-field foul territory and strained the posterior cruciate ligament in his left knee.

Diaz is headed to Atlanta today for an MRI to determine if his injury is worse than a strain. If it's a tear, he could require significant time on the DL.

The Braves plan to activate reliever Rafael Soriano (elbow), who threw a good bullpen session Tuesday, and is ready to return as closer for the first time since early April. The Braves are down to four outfielders and Greg Norton, who can play left field. Also, center fielder Mark Kotsay has missed two consecutive games with back stiffness. Kotsay believes his problem is a day-to-day.

Diaz hurt himself chasing a Prince Fielder foul ball in the sixth inning and stayed in the game long enough to hobble down the first-base line on a bunt attempt in the top of the seventh.

"I banged the wall, and I kind of got a dead leg feeling," said Diaz, who got stitches at the spot on his knee where he hit chain link and concrete at the bottom of the padding.

"The knee kind of went numb. I got up and it started to feel a lot better the more I stood on it. Then I got this bright-idea to test [third baseman] Russell Branyan because he was playing me all the way back on the outfield grass. ... When I took about my fourth step, I realized there was some instability."

Doctors immediately tested Diaz's knee for stability, and an ACL tear was ruled out.

"He said it's possible PCL [tear]," Diaz said.

"I know exactly what that entails. I did my right one my first full season of A ball. [With a] PCL, totally depends. ... On my right knee, I had a grade-two tear, which is pretty bad, and I was playing again in six weeks. It's so much better than the ACL. I know John Elway played his whole career without [a PCL]. Even if it's worst-case scenario, it's fine."