Smart tried to block Jaye Crockett's dunk attempt from behind with 6.2 seconds to go but stumbled out of bounds behind the basket. As he was being helped up, he appeared to exchange words with a fan in the front row before lunging for the fan and pushing him with two hands. The fan, wearing a black Texas Tech shirt, stumbled backward but did not fall.
Smart then walked away, pointing back in the fan's direction. Officials assessed a technical foul but did not eject him, and he remained on the bench until the final buzzer.
The fan who Smart shoved is Jeff Orr, an air traffic controller in Waco, Texas, who travels thousands of miles each year to attend Texas Tech basketball games, according to athletic department spokesman Blayne Beal.
Smart has claimed to Oklahoma State coaches that Orr called him a racial slur, a member of the basketball program confirmed to ESPN.
After the game, Smart was "down and remorseful," the team official told ESPN, claiming that the sophomore guard "got caught up in the moment."
The Big 12 has set up a news conference for Sunday afternoon. Following that, Oklahoma State has scheduled a news conference for 6 p.m. ET at which Smart will speak.
Big 12 commissioner Bob Bowlsby will review the incident Sunday under the conference's sportsmanship policy, a conference official told ESPN. Bowlsby has a number of options at his disposal for Smart, from a private reprimand to a public reprimand to a suspension. Oklahoma State will have the ability to provide its side of the story.
"The Big 12 will talk with parties at both Oklahoma State and Texas Tech in the process of reviewing this matter," the official said in a statement.
Big 12 coordinator of officials Curtis Shaw told ESPN that the officials don't have jurisdiction to eject a player who is involved in an altercation with a fan.
"There is no precedent for that," Shaw said. "Our rules are for flagrant 1 or 2. We don't have grounds for dealing with a fan. We don't have a rule to get involved when the player is involved with a fan. We don't know what was said. The official, Doug Sirmons, didn't know what was said."
Shaw said anything involving a fan is up to the host school.
"That's up to the security of the home team and the conference," Shaw said. "We've never had a fan with a player incident before."
Beal told ESPN that high-ranking officials at Texas Tech already have spoken with Orr. Beal said he is uncertain whether the school will issue a statement about the incident.
"We have never had an issue with [Orr] crossing the line in the past," Beal told ESPN.
A video from a Texas Tech game from 2010 appears to show Orr directing an obscene gesture at Texas A&M player Bryan Davis, but Beal said Sunday that the incident did not escalate.
"We are not endorsing that gesture from the Texas A&M game," Beal said. "It just did not rise up to be any kind of issue."
Davis wrote on Twitter that he remembered Orr but disagreed with Smart's actions.
The same guy that talked crazy to me for 4 years. Smh but you should never put your hands on a fan.- Bryan Davis (@B_Davis0) February 9, 2014
I just saw the video that same fan was at the games talking crazy even when I was in school I don't forget a face he says a lot of crazy ish- John Lucas III (@Luke1luk) February 9, 2014
Out of his mouth when u are in the game. And he is a grown man talking to kids the way he does- John Lucas III (@Luke1luk) February 9, 2014
Lucas also said that in conflicts with fans, players have more to lose.
Former Texas Tech coach Pat Knight called Orr "a great guy" and said he was surprised by the Saturday's altercation.
"He's one of the most loyal fans you'll ever find," Knight told ESPN about Orr. "I was shocked that he was involved. I know he's a crazy fan, a big supporter and a loyal guy, and I know him as a great guy. That's why I was so surprised."
Oklahoma State coach Travis Ford declined to discuss the incident in his postgame news conference.
"I didn't see it yet. I want to make sure I see it and see what happened," Ford said. "I'm still trying to figure it out."
No Cowboys players were made available to reporters after the game.
Oklahoma State (16-7) has lost four straight games and five of its past six contests. Smart, a unanimous selection to the preseason All-America team, had 22 points and four rebounds in Saturday's loss. He was called for three fouls.
The Cowboys next play at Texas on Tuesday night.
Texas Tech coach Tubby Smith said he had turned away from the play and didn't see the altercation.
"You really have to find the film to see what happened," he said. "I assume the officials saw what happened. That's why he got a technical out of it. The frustration when you're losing sometimes on a losing streak, I've been there before, it can be tough. I'm sure he regrets doing that, whatever he did, so things like that happen in the heat of the battle."
Smart is the Big 12's third-leading scorer and is the No. 6 overall prospect on ESPN NBA Insider Chad Ford's latest Big Board.
But Saturday's incident has drawn mixed reaction from NBA executives. One current NBA general manager told ESPN that he does not think Smart's draft stock has slipped as a result of the "overblown" incident, saying that Smart is "too good a kid."
But another current NBA GM told ESPN that he thinks the situation will negatively impact Smart's draft stock.
"When you are loved more for your intangibles than your tangibles to begin with, how can it not?" the general manager told ESPN. "I felt sick for the kid, truly saddened by it."
A former NBA general manager who is currently a scout said Saturday's incident shouldn't affect Smart's draft status, should he declare for the NBA draft, since he will have time to talk about it during the interview process this spring. The former GM said Smart's character hadn't been called into question in the past.
Smart, who decided to return to Stillwater for his sophomore season despite being considered a lock as a high-lottery pick in the 2013 NBA draft, expressed frustration to ESPN this past week about his growing reputation as a flopper and the inconsistency with officiating.
Smart also previously displayed his frustration with emotional outbursts on the court. In addition, he apologized to teammates after struggling through a four-point game against West Virginia in which he kicked a chair on the bench.
However, Smart had said that entering Saturday's game he would have a different mindset.
"I know players are going to go out and take shots at me," he said. "Starting this game, I'm putting it in the back of my mind. If that's how it's going to be played, that's how it's going to be played. If they can do it to me, I can do it also. That's my mindset from here on out. Physically, there's going to be nothing easy."
ESPN.com's Andy Katz and Jeff Goodman and The Associated Press contributed to this report.