The NFL has fined the quarterback $12,500 for his comments, a source told Ian Rapoport of NFL Network.
"I will probably get fined for saying this, but it was pretty bad today," Mayfield said of the officiating.
The game was plagued by flags. There were a combined 19 accepted penalties, 10 of which went against the Browns.
Mayfield took particular issue with a blindside block call on Jarvis Landry that ended a drive in the third quarter.