Melbourne defender Adam Tomlinson needed to be assisted off the ground by trainers early in the clash against North Melbourne.
The defender injured his knee in a marking contest and immediately called for trainers.
He was unable to put pressure on his leg and was taken into the change rooms.
The Demons activated medical-sub Nathan Jones to replace Tomlinson for the rest of the game.
Tomlinson returned to the bench in tears late in the first quarter.