Cannon wasn't penalized on the third-quarter play but Johnson was knocked out of the game and later diagnosed with a knee sprain. Johnson has been ruled out for Sunday's game at Miami.
"It's very frustrating,'' Panthers coach Ron Rivera said of Johnson's injury. "You're going into a game where you lose a guy on something that is an illegal play. Yeah, it's tough. It's frustrating.''
Cannon, a third-year player out of TCU, was thrust into the starting lineup in place of Sebastian Vollmer, who sustained a season-ending leg injury Oct. 27. Cannon reportedly apologized to Johnson after Monday's game.
Other fines from Week 11 included:
Information from ESPN senior NFL Insider Chris Mortensen was used in this report.