Mets' Murphy has right knee sprain

PORT ST. LUCIE, Fla. -- New York Mets first baseman Daniel Murphy will open the season on the disabled list with a Grade 1 knee sprain, securing a spot for Mike Jacobs on the Opening Day roster, general manager Omar Minaya said.

Murphy suffered the injury to his medial collateral ligament during a rundown Tuesday in Grapefruit League action against the Cardinals. Minaya said Murphy would miss two to six weeks.

"I didn't really think it was that bad, to tell you the truth. I just felt it tweak at third base," said Murphy, who acknowledged the knee stiffened Wednesday.

"It's bad timing," Murphy said. "To get hurt, it's unfortunate, but it's a good ballclub and we have some pieces in place, so I just look forward to getting healthy here over the next couple weeks and getting back to New York and helping the team win."

Minaya suggested Jacobs would replace Murphy as the Opening Day first baseman. Jacobs is a former Mets farmhand who was released by the Kansas City Royals in December. He hit .228 with 19 homers and 61 RBIs in 434 at-bats last season.

Jacobs had been battling Chris Carter and Frank Catalanotto for the final bench spot. There now remains room for either Carter or Catalanotto to also make the big-league roster with Murphy headed to the DL.

"I wish that did not happen, but we have to always be prepared," Minaya said. "That's why we come to spring training having signed free agents to minor league deals as insurance."

Earlier Wednesday, Minaya had mentioned that a prolonged absence for Murphy could prompt the organization to bring back prospect Ike Davis from minor league camp. However, the GM decided to leave Davis there. Davis, the son of former major league reliever Ron Davis, hit a combined 20 homers in his first full professional season last year with Class A St. Lucie and Double-A Binghamton. He will open the season with Triple-A Buffalo, Minaya said.

Murphy assumed the first-base role midway through last season, after an adventuresome first half in left field. He hit .266 with a team-high 12 homers and 63 RBIs in 2009.

In other news, the Mets sent outfielder Fernando Martinez down to Triple-A Buffalo. He hit .383 with three home runs and 11 RBIs in 21 games this spring.

Minaya said he wouldn't hesitate to call up Martinez if a spot opened because of injury.

He made his major league debut last May, batting .176 in 29 games before a knee injury ended his season.

Adam Rubin is ESPNNewYork.com's Mets reporter. He has covered the Mets since 2003. Information from The Associated Press was used in this report.