Wigan signed Phelps from Canterbury Bulldogs
Wigan Warriors full-back Cameron Phelps has been ruled out for four weeks with the ankle injury he sustained during Friday's win over Hull KR.
Warriors feared the Australian had broken a bone but a scan has revealed ligament damage.
Coach Michael Maguire said: "It is a lot more positive than when he had the scan - they were concerned it may be up to 12 weeks.
"He is actually able to walk on it too, which is even better."
Maguire added: "He had been playing very well for us - he has been very busy around the ball and defensively working hard.
"He is a loss but we have got someone in position who will do the job for us."
Amos Roberts, who switched from the wing to cover for Phelps against Hull KR, is likely to continue to deputise.