CHAPEL HILL, N.C. -- For the second time in four seasons, North Carolina heads into the NCAA tournament wondering about the health of a starter after a late-season injury.

Coach Roy Williams said he probably won't know until Thursday whether John Henson will be ready for the Tar Heels' tournament opener the next day against the Lamar-Vermont winner.

Henson hurt his left wrist on a fall during the Atlantic Coast Conference tournament in Atlanta. The 6-foot-10 forward didn't play the final two games of the tournament, though he dressed out for the championship game against Florida State.

"If I had to guess -- and this is merely a guess -- if the game were today he probably still would not play today," Williams said Tuesday. "But we're being hopeful that he will be Friday."

It's reminiscent of a toe injury that befell point guard Ty Lawson just before the regular-season finale against Duke in 2009. Lawson sat out the ACC tournament and the NCAA opener before returning in the second-round win against LSU and leading the Tar Heels to the national championship.

That team started its run in Greensboro, about an hour west of the Chapel Hill campus. Now this year's Tar Heels (29-5) are in similar position, with a No. 1 seed and opening in Greensboro.

While Lawson led Williams' fast-paced transition attack, Henson's value comes in defense and rebounding. He's averaging about 14 points, 10 rebounds and three blocks per game, and is a two-time ACC defensive player of the year.

Williams said Henson's wrist swelled during the weekend, but that swelling went down in the past 24 hours.

Senior Tyler Zeller, and sophomores Kendall Marshall and Harrison Barnes didn't sound too worried about Henson's health Tuesday afternoon.

"Selfishly, I missed him (during the ACC tournament) because that's two or three assists a game that are now gone," Marshall said. "He affects the game in more ways than one -- obviously with the double-doubles he puts up on a consistent basis, but more so the shots he alters on a consistent basis on the defensive end.

"That may not show up in the stats, but you can tell teams weren't so worried about attacking us on the inside when the defensive player of the year isn't sitting in there."