Early in the fourth quarter of Melbourne's 22-point qualifying final loss to the Swans at the MCG on Friday night, Lloyd went back with the flight to take a mark at half-forward.
Harmes flew in late, catching the Swan with a forearm to the throat that knocked him to the ground.
The Demon was immediately reported, as Lloyd's teammates rushed in to remonstrate, while Sydney received a 50-metre penalty.
It proved immediately costly for Melbourne, with Lloyd's second goal of the night giving the Swans an 18-point buffer.
Sydney went on to win 14.7 (91) to 10.9 (69), progressing straight to a preliminary final and condemning the Demons to a semi-final against the Lions.
Harmes has played 20 games this season and 142 since making his debut in 2015.
If he is suspended for the clash with Brisbane, it could prove costly.
Harmes has often been used as a tagger and has previously done shutdown jobs on Brisbane superstar Lachie Neale.
The Demons are also likely to be sweating on midfield dynamo Christian Petracca, who battled through a calf issue on Friday night.
