"I can't do anything," Perron told the Associated Press on Saturday night after the Blues closed the season with a 2-0 win over Nashville. "I don't want to get into symptoms but it's still causing some trouble at some points.
"It's tough. It's not easy to deal with."
Perron, a first-round pick in 2007, was hurt on a check by San Jose's Joe Thornton on Nov. 4 but seemed to recover quickly with a goal later in the game. In late February, Perron was still optimistic he'd be back before the end of the season.
"You always think you want to be better," he said. "You're always thinking the next day is going to be the day."
Perron is optimistic he'll be ready for training camp.
"It all depends on a lot of things, but I'm positive," he said. "I'm positive it's going to be good."
Perron finished with five goals and two assists in 10 games. Last season, he had a career-best 20 goals and tied for fourth on the team with 47 points.