The former Magpie, who made a bright start against his old team, rolled his right ankle during the second quarter and attempted to play on before being substituted in the opening moments of the third term.
Scans on Tuesday will reveal the extent of the injury.
"High ankle sprain, it's a bit of a buzz injury," Melbourne coach Mark Neeld said post-match.
"Oh well, he can go sit up in the stand with Mitch (Clark) and James Frawley I suppose."
Neeld said he expected co-captain Grimes, who is on the Demons' long-term injury list, to be available in round 15 against the Sydney Swans, or one week later against Geelong.
He said Clark's foot injury was "a great wait and see" and he would be pleased if the key forward played another game this year.
"The way that it gets explained, the boys say it's a very unique injury," Neeld said.
"The ligament is going well but they had to take the screw out early because it shifted.
"He does four days of rehab and he's got to rest two.
"On the second day that he rests he goes off and sees some very expensive specialist who then tells him what he can do for the next four days.
"How frustrating is that? I get that report every six days.
"So if Mitch plays another game for the year I'll be really pleased. It's that unknown."
Nathan Schmook is a reporter for AFL Media. Follow him on Twitter: @AFL_Nathan
