The second-row has undergone surgery and is awaiting the specialist’s report.
“We’ll know the full extent of it soon,” said Chester.
“Hopefully it’ll be just a repair job and he may only miss around six weeks.
“If there’s some microfractures in there it could be three months but we’ll know more later.”
Kirmond, 32, was injured in Sunday’s win over Widnes Vikings and has been replaced by Liam Finn in the squad for tomorrow’s game at St Helens.
It is the only change to their 19-man squad, although Chris Annakin and Mason Caton-Brown are also pushing for a spot.
n It has been confirmed England will face France at Leigh Sports Village on Wednesday, October 17 (7.45pm) in preparation for the Autumn International Series against New Zealand.