LAWRENCE — One day after becoming the central figure in an end-of-game brawl, and just hours after receiving a 12-game banishment for his role in that incident, Silvio De Sousa poured his heart out.

But in the lengthy apology posted to social media, the Kansas basketball junior forward reserved arguably his seven most important words for the end of the open letter directed to Jayhawk fans.

“I messed up,” De Sousa wrote, “and I am sorry.”

De Sousa’s fascinating-yet-flawed KU career featured its darkest moment Tuesday night.

In the final seconds of the No. 3-ranked Jayhawks’ 81-60 home victory over rival Kansas State, De Sousa had the ball stripped from him at midcourt by the Wildcats’ DaJuan Gordon, who attempted to score a meaningless buzzer-beating layup. De Sousa, though, chased Gordon down and blocked him from behind, sending the freshman guard to the ground and Allen Fieldhouse into a frenzy.

If it all ended there, it would’ve been a rare highlight in what's been a lost season for De Sousa.

Of course, it didn’t end there.

De Sousa hovered over Gordon for several seconds, leading K-State’s Antonio Gordon to fly in and shove De Sousa over. De Sousa retaliated by throwing a punch at K-State’s David Sloan, and when inactive Wildcat James Love joined in, the situation turned chaotic — De Sousa and Love traded blows, KU’s David McCormack appeared to get physical with Love and De Sousa hoisted a metal stool only to drop it moments later.

The hammer came down Wednesday afternoon, with the Big 12 suspending De Sousa (12 games), McCormack (two), Love (eight) and Antonio Gordon (three). KU coach Bill Self approved of the league’s decision, saying he is "disappointed and embarrassed" by the episode.

De Sousa concurred.

“I displayed highly unacceptable behavior that was a poor representation of my team as well as my own character,” De Sousa wrote in his letter, which was posted Wednesday night to Twitter. “There is no excuse for my behavior and I cannot justify the unreasonable choices that I made (Tuesday) on the court. I not only showed a lack of sportsmanship but I put myself, my teammates and the fans in danger.”

De Sousa isn’t eligible to return until the Jayhawks’ regular-season finale, a 1 p.m. March 7 contest at Texas Tech. KU and K-State will meet for Round 2 of the Sunflower Showdown at 12:30 p.m. Feb. 29 in Manhattan.

Tuesday’s fracas was only the latest noteworthy moment in what’s been a collegiate career filled with many highs and lows for the 6-foot-9, 245-pounder out of Luanda, Angola.

De Sousa, who arrived midway through the 2017-18 campaign as a surprise roster addition, struggled as a freshman but came on strong, surging in the Big 12 Tournament and in an Elite Eight matchup with Duke to help that year’s Jayhawk team earn a Final Four berth.

A much-anticipated follow-up season, however, never materialized.

De Sousa’s guardian, Fenny Falmagne, was implicated in documents and testimony during the October 2018 trials of three individuals in the federal government’s probe into corruption in college basketball recruiting. Falmagne was alleged to have accepted or agreed to illicit payments from multiple individuals to steer De Sousa’s recruitment. Former Adidas runner T.J. Gassnola admitted to trying to direct De Sousa to KU, though he testified that no KU coaches were aware of his meddling.

KU at first voluntarily withheld the then-sophomore De Sousa, but midway through the 2018-19 season, the NCAA issued its ruling: De Sousa was ineligible not only for the remainder of that campaign but for his junior year, as well.

“I have always been so grateful for the faith that you all have shown towards me during the last year,” De Sousa wrote Wednesday. “I have been so lucky to have experienced unwavering love and support from not only my family but the University of Kansas and the basketball community. You guys fought for me when nobody else did, and I am eternally grateful.

“It destroys me to think that my actions (Tuesday) overshadowed everything that we have overcome together.”

De Sousa won an appeal for immediate reinstatement this past offseason, but his junior year hasn’t gone as anyone would’ve hoped. The third-string big on a Jayhawk roster with three frontcourt players, De Sousa is averaging just 2.6 points and 2.8 rebounds across 8.2 minutes per game in 2019-20.

Now, if De Sousa is to salvage any part of his third year, he’ll have to take the same route he did as a wide-eyed true freshman: through the postseason.

“I am truly embarrassed by my actions and have let everyone down who has supported me on my basketball journey,” De Sousa wrote. “There is no amount of regret that I can express that will correct this mistake.”