Paul Silas shoved Tyrus Thomas following a postgame screaming match on Sunday, league sources said.
No punches were thrown as several players intervened immediately to separate Silas and Thomas.
Silas was angered by Thomas talking to members of the Celtics on the court. Thomas eventually snapped back at Silas, who was warned not to say anything more or risk a suspension.
Thomas then stood up and Silas pushed him toward his locker.
Rod Higgins met with Silas and Thomas, who both have been fined.
"There was an incident," Higgins told Y! Sports. "We handled it internally and talked to both the player and the coach and moved on. End of story."