Barnes, along with Oklahoma City's Serge Ibaka, got ejected, and Blake Griffin of the Clippers received a technical foul for their parts in a scuffle with 6 seconds left in the second quarter of their game Wednesday night.
Griffin was trying to put the ball up and his arms and Ibaka's became entangled. Barnes shoved Ibaka hard in the chest. Griffin kept trying to get at Ibaka as players from both teams formed a scrum.
After his ejection, Barnes used a derogatory term in a profane tweet that began "I love my teammates like family," but went on to suggest he was tired of backing them up because his actions "cost me money."
Those actions ended up costing him $25,000 on Thursday when the NBA fined him for failing to leave the court in a timely manner and using inappropriate language on Twitter.
"I was completely wrong for pushing Ibaka & then for what I tweeted following the altercation," Barnes posted Thursday on his verified Twitter account. "My poor choice of words & timing do not reflect who or what I am about.
"It was very selfish on my part to make this situation about me instead of my teammates that fought their hearts out & earned a big win against a tough okc team."
Barnes tweeted that he "could have took the easy way out" and claimed that his Twitter account was hacked.
"But that's not what I'm about, I accept full responsibility for all my inappropriate action last night & I am truly sorry!"Suggest a correction