The Flyers have absorbed injuries all season without a significant decline in play all season.

They did it as recently as Game 5 against the Washington Capitals, when forward Mike Knuble was lost for the rest of the opening-round playoff series with a torn hamstring. They just plugged the hole and moved on.

Simon Gagne, Joffrey Lupul, Derian Hatcher, Scottie Upshall, Mike Richards. They all have lost significant time -- Gagne the rest of the season because of concussions -- and the injuries never altered the team's course.

This time, though, they are up against it.

With the Eastern Conference final starting tonight in Pittsburgh, the Flyers have lost Kimmo Timonen, their top defenseman, with a blood clot in his left ankle.

"[Timonen] was hit with a shot in Game 4 against Montreal. He played in Game 5, and it continued to bother him," said Flyers general manager Paul Holmgren. "We had an MRI done on him and followed it up with a visit to a vascular surgeon today; we had a second opinion done today.

"There is a blood clot right in the front of his left foot, right about where he ties his skate. It's a quite serious thing, and he needs to go on blood thinners and he's not going to be available."

Holmgren said doctors told the team that the clot would clear up in a month to 2 months, but that "[Timonen] had a glimmer of hope that he would be able to come back. But it's [Timonen's] glimmer. Right now, we're treating this as if he will not be available."

Timonen said last night he was examined at the University of Pennsylvania by Ronald Fairman, chief of vascular surgery and endovascular therapy, who said there is a chance the clot could clear up in two weeks, depending on how well the blood thinners work, but he did not sound optimistic.

"It's an awful feeling," he said.

The loss is unquestionably the biggest blow to the Flyers this season. In 12 playoff games, Timonen had six assists and was a plus-5.

So now the big question: Who serves the role of Sidney Crosby spoiler and who focuses on Evgeni Malkin, the Penguins' two star forwards.

Timonen would have seen most of the action against Crosby while paired with his young partner, Braydon Coburn. One possible combination could be Derian Hatcher with Coburn.

Hatcher has played a lot against Crosby, but Hatcher is so much bigger than the Pittsburgh forward that playing against him is likely to land Hatcher in the penalty box.

Hatcher would be better matching up against the Penguins' other star forward, Malkin, who is bigger than Crosby and doesn't go down as easily.

Whoever replaces Timonen could also pair up with Lasse Kukkonen, Jason Smith or Randy Jones.

But it will not be easy for the Flyers to find the kind of shutdown pair they had in Timonen and Coburn.