"It turns out he had an 'a-fib' [atrial fibrillation] condition," Stars general manager Jim Nill said. "He'll be out three weeks and should be available close to the start of the season. He might miss one or two games."
Nill said the issue was caught by the team's training staff, which noticed an irregularity in Peverley's EKG during his physical.
"The medical staff did a great job, they recognized this," Nill said. "They picked it up on the EKG, and he's going to be fine."
Nill said the procedure Peverley needed saw doctors shock his heart to have force it back into rhythm, and that while Peverley can skate during his recovery, he is barred from contact.
"I think he's a big part of our team," Nill said. "He's very versatile. You can play him up with good players, you can play him in a second-, third-line role. He's very good on faceoffs, you can play him on the wing. He's won Stanley Cups, been in playoffs, he's been to Finals, and that's the kind of experience you can’t have enough of.
"For three weeks he can skate, no contact at all. After that, he’s good to go for the rest of the season."