The Queensland State of Origin winger appeared to suffer his second hamstring injury of the season while diving for a try attempt in the in-goal.
The Raiders arrived in Victoria full of confidence after winning five of their past six at the Storm's home ground but the hosts won 16-6.
Played in slippery conditions with showers through the first half, the match was a shadow of Wednesday night's epic State of Origin showdown next door at the MCG.
But with Canberra contributing through costly errors, Melbourne did enough to secure the win after leading 6-0 at halftime.
The Raiders had given up 82 points in their past two losses but showed some steely defence in the first half.
The Storm had 60 per cent of possession and forced the visitors into making 229 tackles, coming on the back of five ruck infringements.
It took until the 36th minute for Melbourne to break through their defence and score with prop Josh King finding a hole left by Canberra skipper Elliott Whitehead running out of the defensive line.
After a number of first-half errors Canberra's Kaeo Weekes, playing at fullback, made amends with a 90-metre dash one minute into the second half for a 6-6 scoreline.
But Melbourne again hit the front with dummy half Bronson Garlick finding Shawn Blore who went over.
That margin was pushed out to 10 points when promising youngster Jack Howarth crashed over for his first try in the 51st minute.
Coates was ruled to have knocked on with his try attempt soon after and cut a forlorn figure as he was assisted walking down to the change-rooms, putting his participation in the Origin decider in Melbourne in doubt.
The brave Raiders went down to 15 men after losing debutant Jordan Martin, Ati Mariota and Jordan Rapana to head knocks, with Melbourne marching on to the win.
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