While tweeting about Tuesday's U.S. presidential debate, Mitchell posted a message with a term that is derogatory toward Chinese. He later apologized for using the word, saying he didn't know it was offensive.
"This is obviously an embarrassing moment for all of us," Buono told reporters Thursday as the Lions held a walk-through in preparation for Friday's game against the Edmonton Eskimos. "I know it is for Khalif. For him, this is not who he wants people to think that he is. You can really sense (his) embarrassment."
The 27-year-old from Virginia Beach, Va., was due to return from injury on Friday night but the Lions chose to keep him off the active roster after the league fined him an undisclosed amount.
"When you look at it, there had to be consequences," said Buono. "As a club, we stand for certain things."
As reporters were arriving at the Lions training facility, Mitchell was walking away. He did not work out with the club.
Mitchell will be paid as usual by the Lions, who chose to discipline him even though his absence could hurt their chances of clinching first place in the West Division and home-field advantage in the playoffs along with a first-round bye.
Lions running back Andrew Harris said Mitchell, a self-trained classical pianist who is known for being a gentle giant off the field and vicious on it, has embarrassed the entire team.
"It's kind of putting a black mark on the B.C. Lions right now," he said.
It's not the first time Mitchell has been in trouble this season. Earlier, he served a two-game suspension for hyperextending the elbow of Edmonton Eskimos offensive lineman Simeon Rottier. He was also fined for making a throat-slashing gesture in another game against the Eskimos.
B.C. coach Mike Benevides hopes Mitchell and everyone learns a lesson from the latest incident.
"Right now, it's about making people understand that you can't do that," said Benevides.
The coach added that enough has been said about Mitchell's discipline, because the league and team have taken action and the lineman has apologized. However, Benevides wants the dialogue on curbing racism to continue.
"The more we deal with it and talk about it, I think we'll be better off for it — all of us," said Benevides.