Richard Nelson is one of only two Maryland offensive linemen to start every game this year, but after injuring his right knee Wednesday, he will be fortunate to play again this season.

Nelson has torn a cartilage in the knee, and because a chunk of the cartilage has flipped over, he can't fully extend his leg, trainer J.J. Bush said yesterday.

Nelson is scheduled to have arthropscopic surgery Monday, Bush said.

But Bush added that if the piece of cartilage were to move on its own, thus allowing Nelson to fully extend his leg, Nelson possibly could play right away. If that were to occur, he would play as long as the piece of cartilage didn't move again and then have it removed after the season.

John Rugg, who started the first game at left guard, will go back there to start in Nelson's place, with Mark Agent starting at left tackle. Neither Rugg nor Agent started in last week's win at Wake Forest.

"That's what we'll start with," Coach Joe Krivak said yesterday after practice. "And {Joe} Guiliano will be a backup {at left guard} and {Ben} Jefferson at the tackle. Any of you have any eligibility left?"

If Nelson does miss Saturday's game against Duke at Byrd Stadium, center Bill Hughes would be the only offensive lineman to have started all seven games. If Nelson has the arthroscopy Monday, "he would be lucky if he can be back in three weeks," Bush said.

The likely loss of Nelson further weakens a unit that already is without left tackle John Sorna, who has a sore left foot. Agent was the starter there for the opener, but was moved to backup center after the first week. Jefferson started the second game, but later missed two weeks for disciplinary reasons.

The Terrapins' secondary, which played well last week, also will be shuffled because of injury. Redshirt freshman cornerback Mike Hollis, who has started the first six games, sprained an ankle on the last play of last Saturday's game. It was thought he would be able to play, but the ankle hasn't responded to treatment. Secondary coach and defensive coordinator Greg Williams said J.B. Brown would move from strong safety to right cornerback and Kevin Fowlkes would start at strong safety.

"I think Hollis should be ready by Tuesday or Wednesay of next week," said Williams, whose unit has a tough assignment this week, given Duke's tendency to throw often. "But you can't play on one leg, especially with everything flying around on Saturday."