That would be the foot of Grayson Allen tripping Elon’s Steven Santa Ana. (AP Photo/Chuck Burton)

A tearful apology from Grayson Allen won’t cut it.

Duke Coach Mike Krzyzewski suspended the guard indefinitely Thursday morning for tripping an opponent for the third time since last February. During Wednesday’s game against Elon, Allen was slapped with a technical for sticking his leg out and sending Steven Santa Ana sprawling to the floor. In addition, once he was parked on Duke’s bench after the play, Allen was spotted by cameras throwing a bit of a fit. He had to be calmed down by assistant coach Jon Scheyer.

Although Coach K initially brushed off the incident in postgame comments, he called the act “unacceptable and inexcusable” after receiving a torrent of criticism Wednesday night.

Coach K suspends Grayson Allen — 10 months too late

“We have had the opportunity to thoroughly review the incident involving Grayson Allen from last night’s game against Elon,” his statement said. “As I stated last night, the incident was unacceptable and inexcusable. He took an important step last night by apologizing in person to Steven Santa Ana and Coach Matt Matheny.

“As a program, we needed to take further steps regarding his actions that do not meet the standards of Duke basketball. To that end, we have determined that Grayson will be suspended from competition for an indefinite amount of time.”

Exactly how long that will be is something Krzyzewski said he has not yet determined. “Maybe it’s one game,” he said in an interview on “The Dan Patrick Show.” “I don’t know that right now. Maybe it’s three. Maybe it’s two weeks.”

Indefinite buys time for Coach K, and for Allen. “It gives me time as a teacher to teach…” he said. “There isn’t a Ten Commandments of tripping.”

Krzyzewski continued to insist that he knows Allen “better than anybody” and said that, during the suspension, “I’m going to see where he’s at when he returns. I’ll be in constant communication with him and his parents.” Krzyzewski admitted that he didn’t see the trip, only the foul. “When I saw [him] on the court, he looked like a ghost. I didn’t realize the emotional thing he had just gotten through.”

Krzyzewski had a different reaction immediately after the game, a certain dismissiveness that brought heaps of criticism. “I handle things the way I handle them,” he said. “And I think I’ve handled this correctly, and I will continue to handle it correctly, and I don’t need to satisfy what other people think I should do.”

That was quite the Christmas present for Duke-haters. So was Allen’s emotional reaction after the game.

Allen was tearful after Duke’s 72-61 victory in which he scored three points on 1-for-8 shooting. Calling his act “selfish,” he apologized to Santa Ana, officials and Elon. “Just talking about what led up to it is just an excuse,” Allen said. “There’s no excuse for it.”

Allen made himself the latest Blue Devil to become Public Enemy No. 1 for many college basketball fans last year, when he was involved in two separate incidents of tripping opponents. Both occurred in February, first against Louisville’s Ray Spalding and then Florida State’s Xavier Rathan-Mayes.

Feb. 26: Duke’s Grayson Allen plays dirty, and Coach K declines to put his foot down

Santa Ana now joins the dubious list of Allen trip victims, and as in the previous cases, it appeared that the Duke star was acting as if he had done no wrong and was, in fact, the aggrieved party. Plenty of folks in the stands thought otherwise, booing Allen loudly, while other observers, including former Blue Devil Jay Bilas (who was calling the simultaneous Kentucky-Louisville game for ESPN) expressed incredulity. “I can’t believe he did that in a game,” Bilas said. “I absolutely can’t believe it.”

Yahoo’s Pat Forde couldn’t believe it either and called for a suspension. “Unreal,” he tweeted. “Suspend him already.” He went on to write: “The first incident was surprising. The second was damning. The third is incomprehensible.”

ESPN’s Seth Greenberg added in a comment directed at Krzyzewski: “You’re a Hall of Fame coach. You’re an Olympic coach. . . . Make a statement.”

At halftime of the Kentucky-Louisville game, ESPN’s Rece Davis called Allen’s act “preposterous” while discussing it with analysts Jay Williams, a former Duke player, and Seth Greenberg, a former coach in the ACC with Virginia Tech. “I’m disappointed that he even played in the second half,” Williams said, calling for the junior to get a five-game suspension.

Greenberg agreed that Allen deserved a suspension, saying that “you have to be accountable for your actions.” He added that Krzyzewski “gave him a hall pass twice,” referring to the tripping incidents last season. “Right now, he can’t control his actions,” Greenberg said of Allen. “He needs help.”

Allen has previously expressed an awareness of the reputation he has developed as a dirty player, so it’s possible that the mini-tantrum he threw on the bench Wednesday was born of frustration with the reaction he knew would be coming. “I know there’s never completely a blank slate,” he told ESPN in October, before this season began. “That’s going to be replayed and not forgotten about. But for me, every opportunity I get to step on the court is an opportunity to play the game again and play the game the right way.”

Allen came into the Elon game on the heels of a controversial moment in the Blue Devils’ previous contest, Monday against Tennessee State. While soaring to the basket for an attempted layup, his trailing leg made contact with a defender who appeared to be trying to get out of the way. Allen earned a foul call on the play, while some thought he had committed an expertly executed flop.

For now, this much is certain: Allen will not play against Virginia Tech on New Year’s Eve.