6:03 PM PT -- Chuba and Gundy just released a joint video addressing the shirt incident.
"In light of today's tweet with the t-shirt I was wearing, I met with some players and realized it's a very sensitive issue with what's going on in today's society," Gundy said in the video.
"We had a great meeting, and made aware of some things the players feel like they can make our organization or our culture even better than it is at Oklahoma State."
"I'm looking forward to making some changes, it starts at the top with me. And we got good days ahead."
Hubbard added ... "I went about it the wrong way by tweeting. I'm not someone that has to tweet to make change. I should have went to him as a man."
"I'm more about action, so that was bad on my part. But from now on, we're going to focus on bringing change and that's the most important thing."
Coach and his star player even dapped up at the end of the video ... so, boycott over??
Oklahoma State star Chuba Hubbard -- one of the best college RBs in the country -- says he's boycotting the school after his coach was pictured wearing a shirt supporting a pro-Trump cable network.
Cowboys head coach Mike Gundy was spotted on a fishing trip last week wearing a shirt with the far-right, One America News Network (OAN) logo across his chest.
OAN has become a favorite of President Trump -- but they've been heavily criticized for pushing seemingly baseless conspiracy theories ... including the suggestion that a 75-year-old who was injured by police in Buffalo had connections to the ANTIFA. The man, who suffered serious injuries, denied the allegations through an attorney.
Hubbard -- who was projected to be an early-round NFL draft pick in April before deciding to return to school for his red-shirt junior season -- was so furious with his coach's wardrobe choice, he's now threatening to cut ties with the University.