Perhaps Michel Therrien could find a teacher and borrow an attendance log to keep track of his roster for practice and games.

Or put names on the squares of a Rubik's Cube to see how he can make things fit each day.

The Penguins' coach has spent a fair amount of time recently moving, substituting and reconfiguring, depending on which players are out for various reasons.

And that's in addition to the juggling of line combinations he does on a regular basis.

"With injuries and things like that, guys are kind of feeling things out," team captain Sidney Crosby said yesterday after practice at Southpointe.

That was a session without No. 1 goaltender Marc-Andre Fleury and center Maxime Talbot, who are expected to be out another five-to-seven weeks and one-to-three weeks, respectively, because of high ankle sprains, plus winger Ryan Malone, who was excused so he could get a gash on his leg from a couple weeks ago re-evaluated by a doctor before the team's afternoon flight to New York for tonight's game against the Rangers.

And it was a practice in which winger Jarkko Ruutu left early after a run-in with a teammate's stick left a cut on his face that required stitches. That was not too long after forward Evgeni Malkin spent some time on the bench making sure his left knee was OK after he lost an edge and landed awkwardly during a one-on-one drill.

The workout marked the return of defenseman Sergei Gonchar, who missed Saturday's 3-2 win against the New York Islanders because of a flu-like illness; forward Erik Christensen, who missed that game because of a neck strain; defenseman Rob Scuderi, who left that game after blocking a shot with his left foot; and Ruutu, who got stepped on by the Islanders' Chris Simon.

The forward lines and special teams units looked different accordingly. Kind of a complicated puzzle, and one that's difficult to track -- especially considering the myriad reasons for absences.

Fleury simply moved in the crease early in a game at Calgary Dec. 6 and felt something awkward in his ankle. Talbot missed five games because of his ankle then returned for four games before aggravating it.

Scuderi, who is second on the club with 56 blocked shots, instinctively turned his left foot outward on the one that left him hobbling.

"It hit the wrong spot," he said. "Usually, the feeling comes back when you put some weight on it, but it wasn't coming back."

Ruutu was injured by an opposing player.

Christensen's injury was the most freakish of the latest crop. He woke up one morning with a stiff neck from sleeping on his stomach but worked through that until Friday, when he went hard into the boards during a practice at Southpointe.

"When I landed [in seated position], a shot went right up through my back, and my neck muscles seized right up," he said. "As soon as I woke up the next day in New York, I knew there was no way I was going to be able to turn my head to look over my shoulder."

There's no telling what today's morning skate, tonight's game -- or even an uncomfortable hotel bed or an unsettling meal -- might bring.

"That's something every team faces during the course of the season," Therrien said. "This time of year, you could have some cuts and bruises or guys could be sick.

"It's an opportunity for some guys to show what they're capable of doing. I believe in stability, in pairings with defensemen, with [forward] lines. But you've got to be prepared to give an opportunity to different players. I think it will help us in the long run."

The missing players have opened the door for some teammates to play different roles.

Crosby, for example, is spending more time killing penalties. Defenseman Darryl Sydor has spent more time on the point on the power play. Winger Connor James got to play his first game with the Penguins after a promotion from Wilkes-Barre/Scranton.

"We have a lot of interchangeable parts here," Scuderi said.

With the season more than a third of the way through, the roster revisions come at a time when clubs are looking to meld.

"It's not always going to be smooth. There's always a learning curve for everyone," said Crosby, who, like his coach, sees a benefit to the lineup shuffle.

"This is the time where you really start to figure out things as far as the way it's going to go when the second half starts. Once the second half starts, you want to be pretty much set with roles and things like that. These are perfect situations for guys to get familiar with stepping in and having to do different things. Hopefully, with a healthy team, everything's set after Christmas or shortly after that."