The Oregon coach questioned the timing and place of the act, an apparent demonstration in the wake of a grand jury's decision not to indict police officer Darren Wilson in the fatal shooting of 18-year-old Michael Brown.
Altman reportedly said he was not aware of the players' plans beforehand.
"I think every player has a right to express their opinion, however I didn't think that was the time and place for it," Altman said. "On their own as individuals, they have that right. As part of our basketball team, when you put the Oregon jersey on, it's a little different. So, I think there's a time and place for everything. I don't think that was the appropriate time."
On Wednesday night, Georgetown players wore black t-shirts adorned with the message "I Can't Breathe" before their game against Kansas, a reference to the final words of Eric Garner, who was killed earlier this year after a New York City police officer put him in a chokehold. A number of NBA and NFL players have recently donned apparel bearing the same phrase after a New York grand jury announced on Dec. 3 that it wouldn't indict the officer.