Toronto half-back Joe Mellor could be out for six weeks with a wrist injury.
The 29-year-old suffered a badly bruised wrist in Saturday’s 24-16 defeat at Salford.
Mellor has been named in the Wolfpack’s 19-man squad for their trip to Wigan on Thursday but he is almost certain not to play.
Toronto coach Brian McDermott said: “We managed scans and X-rays but it’s inconclusive at the moment.
“There’s so much swelling about his wrist.
“We’re hoping it’s pretty badly bruised but the worse case is some sort of bone damage and so we could be looking at six weeks.
“We’re down another body but we’ll be right this week.”
Of McDermott’s squad of 23 at the Canadian club, Chase Stanley is still in Australia awaiting the arrival of his visa, Greg Worthington is on loan to Featherstone, Darcy Lussick and Mellor are injured and Sonny Bill Williams has flown back to New Zealand for the birth of his fourth child.