GREENSBORO — N.C. State coach Tom O'Brien came to the ACC media kickoff bearing bad news.

O'Brien, who has seen injuries to key players cripple the Wolfpack throughout his tenure, had another one to announce Monday.

Sophomore cornerback Rashard Smith has not recovered from a knee injury suffered last season at Boston College and had surgery last week to repair a cartilage problem. He will miss the entire season.

The Wolfpack already had lost another sophomore cornerback, Jarvis Byrd, to a knee injury. Byrd is out until at least November, and O'Brien would prefer to redshirt him. Sophomore C.J. Wilson and junior Justin Byers now are the first-team cornerbacks.

"You played five freshmen back there last year, and you've already lost two of them, that's a tough thing for us," O'Brien said. "But once again, it's something that we know about now. But we're still way ahead of where we were last year [as far as injuries], so we're looking for a normal year, maybe?"

O'Brien has yet to post a winning record in three seasons at N.C. State, and serious injuries to players such as Toney Baker, Donald Bowens, Anthony Hill and Nate Irving have played a role in the team's difficulties. O'Brien also cited the 2008 Papajohns.com Bowl loss to Rutgers as a game in which an injury directly prevented the team from having a winning season.

Quarterback Russell Wilson hurt his knee right before halftime in that game and did not return for the second half. The Wolfpack led 17-6 at halftime and lost 29-23.

Nonetheless, O'Brien acknowledged that the team needs better results on the field after finishing 5-7 last season. He is 16-21 at N.C. State with one bowl trip.

"You have to win," he said. "That shows progress, winning, and that's what we haven't been able to do. ... We've got to go on, and we've got to win and have a winning season and go to a bowl game."

O'Brien also said two players who signed with N.C. State in February - former Athens Drive defensive back Pete Singer and place-kicker Billy Bennett - have withdrawn their applications to school for personal reasons.

Singer had numerous brushes with the law, including three citations for driving after consuming alcohol under age 21. In the spring, O'Brien had cited Bennett as an important factor in improving last season's shaky special teams play. N.C. State was counting on Bennett to boot kickoffs into and through the end zone to force opponents into poor field position.

Regarding the rash of the injuries, O'Brien said his staff has analyzed the way N.C. State athletes are trained, coached and treated but hasn't been able to come up with a reason that so many players have been hurt.

"They're all different things," O'Brien said, "and they're not things that are caused by any one source."

ktysiac@charlotteobserver.com or 919-829-8942