The Yankees will wait to get a clear medical consensus on shortstop Derek Jeter's dislocated left shoulder before announcing how long their All-Star shortstop will be out.

New York general manager Brian Cashman on Tuesday said the best-case scenario with Jeter out is six weeks, but Jeter will get a second opinion following MRI results regardless of what team doctors find, ESPN's Peter Gammons reports. Jeter underwent the MRI on Thursday. If he needs surgery, he will likely miss two-to-four months.

Jeter hurt his shoulder in the third inning Monday night in a violent collision with Toronto catcher Ken Huckaby at third base.

The Yankees then will get a consensus and announce the final prognosis for Jeter by the end of this weekend, Gammons has learned. Without surgery, Jeter could return much sooner if the shoulder is able to heal on its own.

Jeter was hurt in the third inning of New York's 8-4, season-opening victory over the Blue Jays after sliding headfirst into third base and colliding violently with Toronto catcher Ken Huckaby.

He was down for more than 10 minutes, writhing in pain and surrounded by worried teammates. Jeter was helped onto a cart by trainers Gene Monahan and Steve Donohue, strapped in place sitting upright and taken off the field.

"I didn't know what happened," Jeter said Monday night. "The worst part is getting it back in."

After the shoulder was popped back in place, Jeter was taken to a hospital for X-rays.

The Yankees recalled Erick Almonte from Triple-A Columbus on Tuesday. Almonte, who will get most of the playing time over backup infielder Enrique Wilson while Jeter is out, homered in the Yankees' 9-7 victory over Toronto on Wednesday.

Jeter was trying to advance an extra base on Jason Giambi's comebacker Monday, an attempt to take advantage of Toronto's defense, which was shifted to the right side of the infield.

Huckaby ran up the line to field first baseman Carlos Delgado's throw. Jeter dived headfirst into the bag and Huckaby fell, his shin guard driving into Jeter's shoulder.

"I didn't mean for things to go down the way they went down," Huckaby said. "By no means was I trying to hurt anybody on that play. It was one of those freak things."

Jeter, MVP of the 2000 All-Star Game and World Series, hit a career-low .297 last season with 18 homers and 75 RBI. His batting average has dropped three straight years, from .349 in 1999 to his first sub-.300 average last season.

Jeter has said part of his problems could have been caused by a right shoulder injury that prevented him from doing upper-body work in 2001 and 2002.

Jeter has been very durable in his career, playing through a variety of nagging ailments and has even tried to hide injuries from Torre so he could stay in the lineup.

He has been on the disabled list only three times in his career, never for more than 16 days at a time.

Also, Yankees closer Mariano Rivera reported no problems after throwing 30 pitches Thursday as he works his way back from a groin injury.

Rivera injured himself the final week of spring training and started the season on the disabled list. He is not expected back until late April. Rivera spent time on the disabled list last June with a groin strain in the same area.

Information from The Associated Press was used in this report.