Belichick's fine was formally for "impermissible physical contact with an official," the league said.
The Patriots coach, who has led New England to three Super Bowl championships, grabbed Esteban Garza's arm after Baltimore kicked a game-winning field goal as time expired that some of his players felt was wide of the goalpost.
Ravens kicker Justin Tucker's 27-yard field goal sailed high above the top of the goalposts and it was initially hard to tell if the kick was good.
"I was really looking for an explanation from the officials as to whether the play was under review and I did try to get the official's attention as he was coming off the field to ask that, but I really wasn't able to do that," Belichick said on Monday.
"I have never meant any disrespect or in any way tried to abuse or be disrespectful to the officials and the job that they do."
The incident drew particular attention given the ongoing row over the performance of replacement referees during the first three weeks of the 2012 NFL season.
The replacements, drawn from the ranks of lower division college, high school and semi-professional football, have been standing in for the regular, unionised, referees who have been locked out since June.
The regular referees were locked after failing to reach accord with the NFL on a new Collective Bargaining Agreement, largely due to a disagreement over pension payments.
The NFL Referees Association and the NFL were in talks on Wednesday aimed at ending the lockout.