CHAPEL HILL — North Carolina sophomore John Henson can shoot, dunk, rebound and block with the best of 'em in the ACC - all potentially game-changing abilities at the end of close contests. But the reason he hasn't been on the floor during the final minutes of the Tar Heels' down-to-the wire showdowns this season is another potential game-changer: his inability to consistently bury free throws.

Entering tonight's game at Boston College (14-7, 4-3 ACC), when another nail-biter could loom, the starting forward knows he has to change that. And soon.

"I feel like I can make big plays at the end - especially defensively," said Henson, who is averaging 10.8 points, 8.5 rebounds and 2.1 blocks - but only 35.2 percent from the foul line. "And having to watch those games from the bench, that's frustrating. But it's completely my fault. ... It's something I've been working on, and hopefully when I prove that I can hit free throws, I will be in there, where I know they [the coaches] want me to be."

Henson has found himself cheering from the bench during three of UNC's closest ACC victories over the last month, negating the possibility that a foe might intentionally put him on the line. The Tar Heels (15-5, 5-1) were leading by two points at Virginia on Jan. 8 when he was yanked with 3:09 left; were up by two, again, when he checked out for good at Virginia Tech with 1:12 left; and had the score tied at Miami when he sat for the final two minutes last week.

Coach Roy Williams said he thinks Henson is working closer and closer to earning his trust on the line, enabling the otherwise-explosive playmaker to remain on the court in the final minutes when a game is on the line. Although the 6-foot-10 forward shot only 43.8 percent from the stripe as a freshman - and is one of only a handful of Tar Heels dating to 1953 to make fewer than 50 percent of his free throws for a season - he was 4-for-8 against N.C. State on Saturday and 5-for-8 at Georgia Tech two weeks ago.

Williams said he doesn't have a hard-and-fast percentage of free throws Henson needs to make to stay on the floor at the end, but "I've got to get more comfortable, and John's got to get more comfortable. He's working at it hard in practice, he's shooting them much, much better in practice, and I see some improvement in the games. ... He's getting closer and closer, but we need him in the game at the end."

It's rather perplexing, Henson's ability to swish a 14-foot jumper yet air-ball one of the most basic basketball shots. (And that's when they're not going wide right or wide left.)

Coaches have tweaked Henson's form a bit, Williams said. But the player said it's his mental focus and confidence that he's working on the most

"You don't really don't want anything going through your head, you just want to clear your mind," Henson said. "At the beginning of the season, my thought process was, 'God, I hope I don't miss.' Or, 'I've got to make it.' So it's just clearing mind, exhaling and just going through the motions.

"That's one thing I've been trying lately, for those two seconds that I've got to shoot the free throws, just clear my mind of anything and everything, and shoot like I shoot every day. It worked the last game, so hopefully I can keep that going."

Williams said he definitely wants Henson in at the end, "because he's such a factor on the backboards, taking away the other team's second shots - and I still feel like the second shot is the one that kills people the most come crunch time. And he blocks some of those shots, as well."

Henson, who made better than 75 percent of his 200 attempts in a recent practice, said he's determined to be there: "I think it's mental, and I'm turning a corner. But we'll see."