Alker has been an ever present for the last two seasons

The 28-year-old hooker suffered medial ligament damage but will not require surgery, and has been advised to rest.

With no other specialist hookers in his squad, coach Karl Harrison has signed David Berthezene on a month's loan from Catalans Dragons.

Alker will be a big loss as he has been ever-present for the last two seasons.

Mark Edmonson also faces at least a month out after dislocating his shoulder, also against Wigan.

The 27-year-old had reconstruction surgery on the same shoulder during his time with St Helens.

"He's smiling and driving his car which is a good sign," said Harrison.

"He had the shoulder put back in hospital and, although it's still a bit tender, he seems alright."

Alker's absence will be a major concern for Harrison, whose side are second bottom of the table.

The hooker has been an ever-present for the last two seasons and with a shortage of cover.