Alex Rodriguez is going on the 15-day disabled list with a strained right quadriceps, leaving the New York Yankees without two of their most important players.

Rodriguez joins injured catcher Jorge Posada on the DL. The Yankees are waiting for additional opinions on Posada’s ailing throwing shoulder before determining whether he needs surgery.

A three-time AL MVP, Rodriguez was sent for an MRI exam Tuesday that revealed a Grade 2 strain. He was put on the DL for the first time since July 2000 with Seattle, when he had a strained right knee.

This is Rodriguez’s fifth career trip to the disabled list.

“If it’s a Grade 2, it’s going to be at least the two weeks. That’s why we’re doing it,” general manager Brian Cashman said.

The Yankees said it hadn’t yet been determined whether Rodriguez would officially be placed on the disabled list Tuesday or Wednesday. Regardless, his stint on the DL can begin Tuesday because the team played without him—and Posada—in a 6-4 loss to the Detroit Tigers.

Rodriguez has been bothered by the injury since getting hurt April 20 in Baltimore. The third baseman missed three games last week, then returned for a four-game series at Cleveland. But he was removed for a pinch hitter in the eighth inning of Monday night’s 5-2 win over the Indians and said he felt a “pull” while running the bases.

Yankees manager Joe Girardi said the team was surprised to learn the strain was so severe. Rodriguez was not available to reporters after Tuesday night’s loss.

“He’s a hard guy to replace,” Girardi said. “We have to find a way to get it done.”

Morgan Ensberg started in Rodriguez’s place at third base Tuesday night.

“Hopefully, it’ll be no more than the 15 days,” Cashman said. “But we’ve got to get it right.”