Players from both teams took part in an extended period of pushing and shoving during the second quarter of their game on Wednesday.
The incident was precipitated by a hard foul committed by Humphries on Boston's Kevin Garnett.
Rondo was the most active of those who took part and he was kicked out of the game, as was Humphries and Brooklyn forward Gerald Wallace.
Wallace was fined $35,000 by the league and Garnett, who picked up a technical foul but was not ejected, drew a $25,000 fine. Humphries was not punished by the league.
Rondo's early departure from the game ended his streak of double-digit assist games at 37, leaving him tied for second on the all-time list with former Utah guard John Stockton. Rondo will miss Boston's game on Friday against Portland and on Saturday against Milwaukee.