Both midfield players were dropped for last weekend's 2-1 defeat at Exeter but Barnes has admitted he is considering changes as he searches desperately for a winning formula.
Barnes said: "Defensively we had to try and be stronger in midfield to help protect the back four because we are leaking goals.
"That's why the decision was made but now we are at home and we have to win matches, so maybe Mahon and Shuker will come back in."
Barnes is confident that goalkeeper Luke Daniels, who is on a season-long loan from West Brom, will be passed fit after he missed the Exeter defeat because of a knee injury.
Striker Bas Savage (Achilles) remains a long-term absentee.