Penguins center and captain Sidney Crosby is expected to be re-evaluated by concussion specialist Michael Collins in the next week or so, general manager Ray Shero said Friday.

Crosby, who was on vacation in Europe, has returned to Pittsburgh. He will need clearance before he begins an offseason workout program.

Crosby was leading the NHL with 66 points in 41 games when he was diagnosed Jan. 6 with a concussion. He did not play again but recovered enough to practice with the Penguins -- minus contact -- before he began having headaches again in late April.

The team and Crosby have said they expect a full recovery in time for the 2011-12 season.

In the meantime, Shero said two of the club's impending free-agent forwards -- Mike Comrie and Alex Kovalev -- won't be re-signed.

"I'm not sure what Mike's going to do," Shero said. "He might be leaning toward retirement."

Comrie, 30, was signed as a free agent last summer. He had a strong preseason but sustained a right hip injury in the second game of the season that eventually required surgery in December. He returned to play sparingly late in the season, finishing with one goal, six points in 21 games. He did not crack the lineup in the playoffs.

Kovalev, 38, was acquired from Ottawa in March but did not flash the strong offensive flair he had in his earlier tour with the Penguins. He had two goals, seven points in 20 games, then one goal, two points in seven playoff games. None of the three goals came on the power play.

Shero said he would not rule out bringing back any of the other forwards who are eligible for unrestricted free agency if not re-signed by July 1. They are Max Talbot, Pascal Dupuis, Mike Rupp, Craig Adams, Arron Asham, Eric Godard, Chris Conner and Nick Johnson.