ROCHESTER, N.Y. -- As his University of Maine teammates skated in its final practice before tonight's NCAA tournament opener, Keenan Hopson sat on the team bench in his warm-ups.

No helmet or pads. No skates.

For now, Hopson is a medical scratch.

Hopson underwent an emergency appendectomy Tuesday night that will keep him out of the lineup this weekend. Hopson was a key center for Maine before being converted to a defenseman during the Hockey East quarterfinals to help shore the team's defense.

"Keenan, yeah, he's great with the puck and confident back there," said defenseman Mike Lundin. "It's tough to lose him especially in this situation. But I think guys will be able to step in no problem."

Hopson said a pain in his lower abdomen grew increasingly worse Monday night as he watched a movie with his roommates. By the wee hours of the morning he went to Eastern Maine Medical Center.

"By the end of the movie I couldn't even lay down," said Hopson. "I tried to sleep but started to puke and stuff. And my roommate took me to the hospital at like three in the morning."

Hopson filled in nicely at defense during his two games there, giving the team some more poise at the position.

"Yeah, I like to make things difficult," joked Hopson.

Sophomore Bryan Plaszcz will fill his spot on defense for tonight's game, and Saturday should Maine reach the final.

"It's unreal. Up until a couple of days ago I didn't think I'd be playing in this tournament," said Plaszcz. "I'm going to have to keep it simple. I've been waiting to (play in the NCAA tourament) for as long as I can remember."

Hopson said should his team advance to the Frozen Four April 5-7 he believes he will be ready to go. The experience also gave him some perspective.

"It (stinks). But when they said you might need surgery hockey is hockey," said Hopson. "I wanted to make sure I was fine. I wish I was out there. But hopefully in a couple of weeks."

NOTES: Maine holds a 5-1-1 advantage over St. Cloud in the two teams seven meetings. . . Maine's lines are expected to be similar to the ones it used against Massachusetts in the Hockey East quarterfinals, with the exception of DeKastrozza filling in for Tony Morrone on the third line. First line -- Josh Soares, Michel Leveille, Keith Johnson; second line -- Billy Ryan, Mike Hamilton, Teddy Purcell; third line -- Brent Shepehard David DeKastrozza, Rob Bellamy; fourth line -- Chris Hahn, Wes Clark, Vince Laise.