Two Rams players were caught by the ESPN broadcast in a heated argument on the sideline.
Linebacker Justin Hollins and defensive lineman Takk McKinley exchanged words and bowed up on each other before several teammates intervened, separating the two players.
Director of football affairs Jacques McClendon got McKinley away from the position group for a chat.
It is unknown what started the disagreement.
Things have heated up on the field between the division rivals, too, with some extracurriculars.
The 49ers lead 17-9 with 8:38 remaining after Robbie Gould missed a 42-yard field goal. The Rams are 0-for-3 in the red zone and the 49ers are 0-for-1 in the red zone.
The 49ers have ruled out defensive lineman Arik Armstead, who entered the game questionable with a foot injury.