Medhurst limped from the ground with an injured ankle 13 minutes into the match and went straight to the rooms.
By quarter time, Medhurst had still not emerged from the rooms.
The injury further compounds Collingwood’s injury woes, with Anthony Rocca and Heath Shaw both last-minute withdrawals.
The pair was replaced by Sharrod Wellingham and Anthony Corrie, who are playing their first matches of the year.
Despite the absence of two of its key forward targets, Collingwood held a five-point lead over North Melbourne at the first change.
