Sean Spence is about to miss a game for the first time as a Miami Hurricane.

The sophomore's No. 31 jersey, replicated by Nike in two colors, might be worn by Hurricanes fans scattered around BB&T Field in Winston-Salem, N.C. But the real No. 31 -- the 2008 Atlantic Coast Conference Defensive Rookie of the Year -- is out for Saturday's Wake Forest game because of a knee injury.

``Hopefully, he'll return this season,'' UM coach Randy Shannon said Tuesday. ``But we just don't know when.''

Spence injured his left knee against Clemson last Saturday, then insisted he could go back in the game after halftime. He was taken out when it became apparent he was too hobbled to play. Shannon said he hasn't had surgery, and didn't elaborate or reveal the specific injury.

Quarterback Jacory Harris said he hardly could believe it. He and Spence are close friends and played together at Miami Northwestern High.

``He's kind of down about the injury,'' Harris said. ``I'd never seen Sean hurt until the beginning of the year, when he hurt his quad. Now this.

``I had never seen him him lying on the ground hurt. It kind of shocked me. I was like, `Sean, you're all right, right?' He was like, `Man, my knee keeps hurting and I can't really run.'

``Then, you know, he got back in for a second time and he really hurt himself again. He's going to be a big loss for this defense.''

BUCHANAN'S TURN

No. 18 Miami (5-2, 2-2) already was without top reserve linebacker Jordan Futch, who tore his anterior cruciate ligament recently. UM will face the Demon Deacons (4-4, 2-2) with replacement Ramon Buchanan, who plays special teams and has filled in on the outside.

Spence started all seven games and played on the weak side. He is fourth on the team in tackles with 35 and has 5 ½ tackles for loss. He also has two sacks, a pass breakup and quarterback hurry.

``Against Clemson, when Sean went down, Coach put me in and I played good,'' Buchanan said. ``I played a lot of snaps last week. I'll probably play a lot more snaps this week because we all know Sean is down for a little bit right now.''

Buchanan, a sophomore out of Melbourne Palm Bay High, is 6-1 and 215 pounds. He has nine tackles this season, mostly on special teams.

Strong-side linebacker Colin McCarthy leads UM with 49 tackles, with 6 ½ tackles for loss, an interception, a forced fumble and pass breakup. Middle linebacker Darryl Sharpton ranks second with 46 tackles, with 3 ½ tackles for loss.

Shannon said Buchanan ``is developing'' and ``still has some things he needs to learn and concentrate on. But he has done a great job to get himself in a situation where he can help us out.''

The other two linebackers who will rotate, if needed, are junior Kylan Robinson and sophomore Arthur Brown.

Safety Randy Phillips said Buchanan is eager for the opportunity.

``He's very athletic,'' Phillips said. ``He's light, quick on his feet, one of the faster guys on the team. His instincts are good. He plays hard without a lot of thinking and that's what we need right now, someone who is going to run, play hard, play great defense without all the hesitation.''

The uncertainty at linebacker should force UM's defensive line to compensate by being more aggressive.

The linemen have not put enough pressure on the quarterbacks this season, giving players such as Clemson's Kyle Parker lots of time to develop plays.

``We just have to get better up front,'' Shannon said. ``We have to get the right combination in there to get to the passer.''

BAILEY MOVES TO END

Shannon will move Allen Bailey from defensive tackle to end this week. Bailey had two sacks last Saturday, one resulting in a Parker fumble. End Marcus Robinson scooped the ball up and ran 46 yards for UM's first defensive score of the season.

``If you get pressure, the quarterback doesn't have time to set his feet and he makes bad throws,'' Robinson said. ``We need to make more plays in the backfield to create open scenes for our linebackers. It gives them more time to see the play develop and know where to fit.''

Said Phillips: ``Plays like that excite the crowd and help the defense with motivation. We need the same thing this week to get points and get momentum and build a swag for the defense.''