"Although he's been able to do more, he really hasn't been able to eliminate all of his symptoms," Flyers team physician Gary Dorshimer said Wednesday. "He's still having these symptoms and I can't clear him to go back to full activity."
Primeau, 34, made the announcement official Thursday at the Flyers' practice facility.
The Flyers, who open training camp Friday, are ready to move on without their former captain.
"The last time I talked to Keith, I said, 'You don't want to become a distraction. If you can't play, we have to go on without you,'" general manager Bob Clarke said Wednesday.
Primeau seemed set to face the harsh reality that his career could be over on Tuesday night, saying, "you could read it on the wall."
Primeau had been trying to return from a concussion sustained on Oct. 25 after a hit from Montreal's Alexander Perezhogin. It was the most severe in a series of head injuries Primeau endured during his 15-year NHL career.
"He never gave any indication to anybody that he was going to come back," Clarke said. "We felt all along that he wasn't going to come back. We've got to start training camp with the players we're trying to make a team of."
Primeau, who has two years and $6.84 million remaining on his contract, missed 21 games because of a concussion sustained against the Rangers in the 2003-04 season. He also had at least two head injuries during the 2004 playoffs, in the Eastern Conference semifinals against Toronto and in the conference finals against Tampa Bay.
Primeau matched his career high with 73 points in 2000-01 and led the Flyers in playoff goals (nine) and points (16) in 2004 when he helped lead them within a win of the Stanley Cup finals.
"I think Peter is the obvious choice for our team," Clarke
said in a statement. "Not only is he our best player, but he's
also won a Stanley Cup. He's experienced enough to know what the
game needs and what the team needs to be a winner.
"We felt all along that he was the right guy, and he'll be a
good captain for us."
Chosen in the first round by Detroit in the 1990 draft, Primeau spent six seasons with the Red Wings and three more with Hartford/Carolina. After missing the first half of the 1999-2000 season with Carolina because of a contract dispute, Primeau was traded to the Flyers and brought immediate toughness and leadership to the locker room.
He finished with 266 goals and 619 points.
"He was a good player and a great leader," Hitchcock said. "That's a great combination."
Information from The Associated Press was used in this report.