Winger Low strained a thigh muscle in training last Friday which forced him to miss Saturday`s 1-1 draw at Oxford and Tuesday`s 2-1 defeat at Wycombe.
Manager Mark Yates will assess his condition as late as possible before the club`s third away fixture in the space of a week.
Centre-back Riley made his comeback from hamstring trouble last Saturday but was rested to the bench at Adams Park. He comes back into Yates` thoughts against the Shrimps.
The Robins are hopeful fellow defender Andy Gallinagh (double hernia operation) will be back in training in a fortnight with a view to being match ready towards the back end of February.
On-loan striker Phil Walsh has returned to parent club Dagenham in search of more regular first-team football.
Source: PA
Source: PA