Nate Sheppard questionable for Duke vs. UNC on Saturday

The news broke Wednesday night, and it came from 2 of the best-sourced college football reporters around, minutes apart.

Pete Thamel

@PeteThamel

Duke star tailback Nate Sheppard is questionable for the UNC game.

Pete Thamel had it first. Pete Nakos followed with the detail that matters for anyone planning their Saturday: Sheppard is day-to-day, according to his sources, so there is no long-term diagnosis and no ruling either way yet.

Pete Nakos

@PeteNakos

Duke Heisman hopeful running back Nate Sheppard is questionable for this week's rivalry game against North Carolina. Sources told @On3 that he is currently day-to-day. t.co/wXZrtHUVGA

The injury hasn't been officially named, but there's a pretty obvious suspect. Sheppard reportedly played through a left ankle injury in last week's road loss at Georgia Tech, making a trip to the medical tent in the first half and limping after plenty of his touches. He kept going anyway. That's what makes this week's questionable tag so nerve-wracking in Durham. If he could play through it 6 days ago, why is it still in doubt?

Here's why this matters so much. Sheppard has been the whole show. Through 5 games he has 743 rushing yards and 8 touchdowns on 118 carries, plus 17 catches for 161 yards and 3 more scores. He leads FBS in rushing yards per game at 148.6 and in all-purpose yards per game at 180.8. He's forced 38 missed tackles and piled up 495 yards after contact. Before this week, he hadn't had a game with fewer than 124 scrimmage yards. Duke is 4-1, and the Heisman buzz is real.

Bill Belichick knows it, too. The UNC coach spent his week talking about Sheppard like he was the only guy on the Duke roster: "If you let Sheppard out, you're gonna pay for it." He also pointed out that Illinois, Stanford and Georgia Tech have all had trouble with him. If Sheppard can't go, Belichick's whole defensive game plan gets thrown out, and Duke has to find out what the offense even looks like without him.

And this isn't some random Saturday. It's the Victory Bell game, at Wallace Wade Stadium, 3:30 p.m. ET on ESPN2. North Carolina comes in at 3-2 and would like nothing more than to catch its rival without its best player. Duke is coming off a loss and needs to stop the slide before it becomes a skid.

What to watch: Duke's availability reports the rest of the week, and especially the final one right before kickoff. A day-to-day tag on a guy who already played hurt last weekend reads like a real game-time decision. Keep an eye on the line, too. If Sheppard sits, Vegas will move fast, and the bettors who saw this coming will be the ones laughing on Saturday night.