Although his injury wasn’t as bad as originally thought, Rick Reed was placed on the 15-day disabled list yesterday in order to make sure his injured left calf muscle heals completely.

Reed hurt the muscle trying to stretch a single into a double in Sunday’s win in Montreal. It was originally thought to be an injury to his Achilles tendon, but an MRI yesterday revealed a slight tear to the calf muscle and no damage to the Achilles.

Much like they did with Mike Piazza and the catcher’s injured knee, the Mets decided to be cautious with Reed – who has had difficulty with his Achilles tendon for much of the spring – rather than risk a more long-term injury.

“We hope to eliminate the problem before it becomes a problem all year,” GM Steve Phillips said. “It’s highly likely that at the end of 15 days he’ll be activated and can pitch.”

Allen Watson (1-0) is scheduled to take Reed’s start on Sunday. The Mets called up lefty Rigo Beltran, who struck out the side in the ninth, to replace Reed on the roster.

Reed was wearing a stabilizing brace on the calf before yesterday’s 8-1 win over the Marlins, but was walking around without much visible problem.

“This gives it a chance to heal,” Reed said. “Why go out and keep tearing it up? This gives it a chance to heal so I can pitch the rest of the season.”

Reed is expected to throw off the mound in three or four days.