Skipper Purches should return to the back four after missing last weekend's 4-0 defeat at Huddersfield through illness, and the right-back will continue to play in a protective mask following his recent fractured cheekbone.
Chambers now has three reserve games under his belt after six weeks out with a calf injury and he is also ready for a first-team return.
Goalkeeper Jamie Jones (head) and midfielder Sean Thornton (knee) resumed training this week following their recent lay-offs but neither will be risked.
Left-back Charlie Daniels had to come off after an hour last weekend due to illness but he is fine.
