The Brazilian frontman had to be substituted an hour into Saturday's 4-1 win over Swindon after picking up a knock.
Lee Barnard replaced Guly and scored Saints' fourth goal to push his claims for a return to the starting line-up.
Defender Dan Seabourne and forwards Jonathan Forte and David Connolly sat out at the weekend with minor niggles and could feature but full-back Ryan Dickson remains doubtful with a neck injury.
Winger Lee Holmes is recovering from an ankle operation, and back-up goalkeeper Bartosz Bialkowski has a knee injury which may require surgery meaning Arsenal loanee James Shea will be on the bench again.
Source: PA
Source: PA