ATLANTA -- The Mets placed left fielder Moises Alou on the 15-day disabled list before Thursday night's game with the Braves with a strained left calf.

The Mets bought the Minor League contract of Raul Casanova to fill the roster spot. He will be used as a backup catcher and primarily in pinch-hit situations.

Alou left Wednesday's game against the Braves in the third inning. When Alou walked off the field with one out in the inning, he initially thought it was just a cramp in his left calf, but was later diagnosed with a strain. Marlon Anderson filled in for Alou in left field during Thursday's series finale.

"To tell you the truth, being realistic about it, I'm not very optimistic about it," Alou said after Wednesday's game. "It doesn't feel very good. Last time I had my left calf [injury] I don't think I went on the DL, but I took a few days off."

Alou flew back to New York to have an MRI and did not rejoin the team in Atlanta.

"It sounds like some type of strain with his calf, and those are always delicate injuries and we'll probably have to make that move later on," Mets manager Willie Randolph said.

Alou was activated from the 15-day disabled list on May 2 after missing more than a month recovering from hernia surgery.

"It's like my career is now always two outs with an 0-2 count," Alou said before Wednesday's game.

In 47 plate appearances this season, Alou is batting .340 with seven RBIs. Alou played 14 of the Mets' 18 games since returning from the DL.

Alou missed more than two months last season after straining his left quadriceps muscle.

His replacement, Casanova, has played the last six games with New Orleans, the Mets' Triple-A Pacific Coast League affiliate. He was 9-for-18 with three RBIs.

The only other option the Mets have in the outfield is Fernando Tatis, whom Randolph said played the position in the Minors and college.

Outfielder Angel Pagan has been on the DL since May 13 with a left shoulder contusion, but may not be ready when he is eligible to be activated next week.

Damion Easley missed Thursday's game because his son, Rocky, graduated from high school. Easley will join the Mets when they play this weekend's series with the Rockies.

Right fielder Ryan Church sustained a mild concussion in Tuesday night's game, and was not in the starting lineup again Thursday. Randolph said that if Church appeared fine after a pregame workout, he may be used as a pinch-hitter.

Church reported before the game that he felt whiplash on both sides of his neck. He is expected to be ready for this weekend's series against the Rockies.