McCollum was fined $20,000 for shoving Len and attempting to escalate the altercation. Len was fined $15,000 for shoving McCollum.
The incident, which resulted in technical fouls for both players, occurred with 8:50 remaining in the third quarter of the Kings' 123-111 win over the Trail Blazers on Saturday.
McCollum and Len engaged in a physical altercation and had to be separated with the Kings leading 80-60. After a review, Len was called for an offensive foul for a screen. Although both players put their fists up, neither threw a punch and both stayed in the game.
"I think that's Alex's second scuffle or what you'd call a fight in today's NBA," Sacramento coach Luke Walton said. "You need to play with an edge, and the only way to play with an edge is to have guys who have that in their makeup. We've only had him for a short time, but he's definitely made us a tougher, more physical team."