Basically, a mulligan is a second chance with no penalty for the first try. It's most often available on the opening tee box, but it can be used in other situations. If a mulligan is taken, a duffer will hit two tee shots to start a round, select the better one, pick up the other ball and proceed as if the discounted shot never occurred.

The NCAA Tournament begins this week, and for a UNC team filled with veterans who have seen and done everything there is in college basketball, except one thing, their mulligan is available this week.

The Tar Heels (28-4), seeded No. 1 in the South Region, will play Radford (21-11) in an NCAA Tournament first-round game at the Greensboro Coliseum at approximately 2:50 p.m. Thursday. If the Tar Heels win, they will advance to the second round on Saturday in Greensboro to play the winner of the preceding LSU-Butler game.

On what was supposed to be his last hole of golf last summer, before he put his clubs away for basketball season, Williams found himself stuck in a difficult situation around the green and actually shot a 22 on that hole, the UNC basketball coach recently confessed.

Williams and his playing partners opted to extend their round and played one more hole. So, as it turned out, he walked off his last green with a par, not a 22.

The closest thing Carolina gets to an extra hole is the NCAA Tournament.

A 73-70 loss to Florida State in the ACC Tournament semifinals ended the Tar Heels' stay in Atlanta this past weekend, but now they can take their mulligan and end their season with a victory.

If they do, it will mean they are NCAA champions. If they lose, they will return to Chapel Hill and try to figure out what went wrong with a team that appeared destined to win the title three years ago when freshmen Brandon Wright, Wayne Ellington and Ty Lawson joined a talented group of sophomores that included star Tyler Hansbrough.

No one ever expected to see this group remain together for three seasons and, really, it hasn't.

Wright stayed one year before leaving for the pro ranks, and the 2007 team made it to the round of eight in the NCAA Tournament before losing to Georgetown that one season he played.

Last year, the Tar Heels advanced a step further before losing to Kansas in the Final Four semifinals.

Remarkably, Hansbrough returned for his senior season rather than turn pro, and so did the rest of the Tar Heels, Lawson in particular. Senior Marcus Ginyard underwent off-season foot surgery, but he was supposed to return within a couple of months, ready to go.

When practice started back in October, this team looked as if it might be invincible. What happened instead was a continuing saga of injuries that has plagued this team for so much of its existence.

Hansbrough, who had missed only one practice in three seasons, had to sit out several games with shin problems and a sprained ankle. Ginyard was never able to return and ended up sitting out the season. (He is expected to return in the fall.) Now Lawson's toe is the focus of concern.

Lawson jammed his big toe on a basket support during a practice in the final week of the regular season. He played against Duke in the regular-season finale after taking a pain-killing shot, but playing in that game caused the injury to worsen even more.

So, he sat out the ACC Tournament and, without his play on the court, Carolina came home early.

Lawson is the key to how far this team advances in the NCAA Tournament. If his toe is fully healed or is close enough that he can fully utilize his talent, Carolina has as good a shot as anyone to win the national championship. If Lawson continues to struggle with the injury, even if it's just enough to keep him from being his true self on the court, the Tar Heels' chances diminish.

When this is over, there won't be an optional do-over. No more mulligans. The year will end then and there.

And there will end the college careers of Tyler Hansbrough, Bobby Frasor, Danny Green and Mike Copeland. Probably for Lawson and maybe Ellington too.

So, this is it. No extra holes.