Alcock turned his ankle in the warm-up before the Glovers' 0-0 draw at Millwall on Tuesday and although he played through the pain barrier for the first half, he needed to be substituted at half-time.
His replacement at the interval was Andy Lindegaard, and the former Cheltenham defender will start against the Latics if Alcock fails to prove his fitness.
On-loan Brighton forward Craig Davies is expected to keep his place on the right wing.
Davies, 23, made his first start in Tuesday's draw following a groin injury to Ryan Mason.
On-loan Tottenham striker Jon Obika is on international duty with the England Under-20 squad and again misses out.
Source: Team_Talk