It would be the first in a series of fines to stem from Sunday's contentious game against the Bears, who won 37-13 in Soldier Field.
Officials review all plays involving potential violations, even if not penalized during the game, and they are referred to Ray Anderson and Merton Hanks, executive vice president and vice president of football operations, respectively.
The two have plenty of plays from which to choose, ranging from hits on quarterback Jay Cutler by Lions defensive tackles Ndamukong Suh and Nick Fairley, to the fourth-quarter brawl between the teams that resulted in the ejection of Bears cornerback D.J. Moore.
Bears coach Lovie Smith on Monday said Lions quarterback Matthew Stafford should have been ejected along with Moore following the altercation. Moore charged Stafford, who dragged down the cornerback by grabbing the back of his helmet and his face mask during an interception return by Tim Jennings.
Moore has said that he expects to be fined.
In a non-fight related offense, Bears wide receiver Earl Bennett was fined $10,000 for wearing orange cleats in the game, according to a league source.
Bennett was fined $5,000 the previous week for the same offense -- a violation of the NFL's uniform policy -- in the Bears' 30-24 victory against the Eagles.
Information from ESPN NFL Insider Adam Schefter and ESPNChicago's Michael C. Wright was used in this report.