There will be much wider actions in the coming days imo.
McKenna has been training with Essendon.
Essendon Played Sydney last week.
Sydney Played North Melbourne this week.
I' wouldn't at all be surprised if all staff and players at all three clubs were directed to self-isolate for the next two weeks minimum as part of the standard contact-tracing protocols.
I guess that could potentially happen if there is a risk that another player had been positive at the time.
I think it is more likely that the current fixture gets shuffled and adjusted to play midweek games if Essendon are not able to train/play for a fortnight due to isolation requirements.
For example as Essendon are due to play Melbourne in Rd 3 and Carlton in Round 4 those clubs could have played on Thursday night with the current Thursday night pushed back a couple of days. The problem is those clubs have already played so there would need to be another solution with a fixture adjustment in one or more of the other Round 4 games.