Clark said: “This is a really important game for us. If we’ve got aspirations to be in the top six then we’ve got to look to get something out of this match.”
In-form Oldham have won four of their last six games, but coach Scott Naylor is not complacent.
Naylor is hoping to confirm a loan deal with Halifax’s Anthony Bowman in time for Sunday’s match.
David Cookson is also available for the Roughyeds, but Mo Agoro (ankle) is facing a race against time to prove his fitness.