Rory Fallon will not feature for hosts Aberdeen after boss Craig Brown said he had sent the forward to a specialist over a niggling injury.
The former Scotland boss added that Teenager Cameron Smith is in the frame for a start, as is Northern Ireland forward Niall McGinn. Striker Vernon has struggled for goals recently and could be rested for one of the aforementioned pair.
Skipper Russell Anderson will start after his red card was overturned. Gary Naysmith (hamstring) and Rob Milsom (knee) remain on the sidelines.
Motherwell boss Stuart McCall has a full selection of players available after overcoming a few doubts earlier in the week, although Steven Saunders is a long-term absence as he recovers from a knee operation.
Motherwell are top of the SPL with 12 points from six matches, although Celtic and Dundee United are four points behind with a game in hand.