ATLANTA -- Evander Holyfield had tests Monday on the left shoulder he injured in losing his IBF heavyweight title fight to Chris Byrd.

Holyfield's manager, Jim Thomas, said results of the MRI will probably not be known until Tuesday.

Holyfield, 40, said he injured the shoulder in the first round of Saturday's fight in Atlantic City, N.J., with Byrd, who won a unanimous decision over the former four-time heavyweight champion.

Thomas said one doctor thought Holyfield may have damaged his rotator cuff, which he also injured in a fight against Michael Moorer in 1994.

Holyfield used his left hand sparingly against Byrd, and was credited with landing only three jabs against the new champion.

Holyfield said after the bout he would continue to fight toward his goal of winning the undisputed heavyweight title once again. He has won only two of his last seven fights, going back to a draw in his first fight with Lennox Lewis.

Thomas, though, said if the shoulder injury is a chronic one, there is a chance Holyfield might stop fighting.

"It's conceivable someone could convince him his shoulder will be a problem, in which case he would re-evaluate things," Thomas said. "He hasn't said he would go on whatever happens. If there is an injury that keeps him from being his best, he may not fight anymore."