PINEHURST Wolfpack sophomore running back Mustafa Greene will miss at least the first four games of the season because of a foot injury, and Pack sophomore cornerback Jarvis Byrd will miss the season because of another ACL injury, N.C. State coach Tom O'Brien said Monday.

Greene, who suffered his injury in spring practice, has a target return date of Oct. 1, O'Brien said.

"We have to wait until he gets healthy," O'Brien said. "We're going to be cautious. A week later is better than a day earlier."

Greene led the Wolfpack with 597 rushing yards last season and scored six touchdowns. N.C. State has not disclosed the nature of the injury or to which foot. O'Brien said Greene did have surgery.

Without Greene, junior James Washington and senior Curtis Underwood are listed as the top two players in the organizational chart at running back. Freshman Tony Creecy, who redshirted last season, and junior Brandon Barnes will also be in the mix. Creecy, who was a prep star at Southern Durham, is considered the best long-term prospect of the group.

Meanwhile, Byrd, who missed the 2010 season with a knee injury, injured his other knee 10 days ago in an offseason drill. An MRI on Friday revealed an ACL tear, O'Brien said.

Byrd was listed as the starter at boundary corner headed into fall camp. State still has C.J. Wilson and David Amerson, who started last season, and Rashard Smith, who is also returning from a knee injury after missing all of the 2010 season.

No contact for Houston: UNC tailback Ryan Houston, who had shoulder surgery after spring practice, will go non-contact when the Tar Heels open fall practice Aug. 5.

"In talking to ... our trainer, he's not going to be available for contact until probably somewhere between the 10th and the 15th of August," UNC football coach Butch Davis said. "And then obviously, we're going to be extremely smart about what you bring him back to do. You don't put him into a 70-play scrimmage the very first day. Let him get hit a little bit and build his confidence back up. We fully expect at this time that he'll be ready to go at the start of the season."

Houston redshirted last season, after rushing for 713 yards and nine touchdowns in 2009.

Cutcliffe on Renfree: What does Duke coach David Cutcliffe hope to see out of quarterback Sean Renfree this season?

"To pick up where he left off," he said. "The second half of the season, he really took care of the football. He needs to utilize his athleticism, and if he does that and what he did in the second half of the season, he can be a great player."

Renfree finished second in the ACC in total offense and third in passing yardage last season, and had one streak of 165 passes without an interception. And Cutcliffe said second-year starters generally show a vast amount of improvement.

"They've seen just about everything they're going to see," he said. "It's like a baseball batter seeing a pitcher for the third or fourth time. They usually hit him better. Once you've seen all the coverages ... and all that, you're much more comfortable."

Employment is good: Wake Forest coach Jim Grobe was asked if there are any perks to being the dean of ACC football coaches, considering he has the longest tenure in the league (he's beginning his 11th season.) "It's a great perk just to have a job," he quipped.