The injury kept the 29-year-old on the sidelines for much of 2016 after he ripped the muscle off the bone.

Mullen hoped to be back for the Knights’ round one clash against the Warriors, however, the halfback conceded he might not return.  

“If it keeps going it will be pretty hard to get back,” Mullen told Fairfax Media.

“I just have to be patient with it, and hopefully it gets stronger before the start of the season.” 

Mullen’s unavailability throughout 2016 caused serious headaches for Newcastle with the newly-signed Trent Hodkinson having to be paired with an array of inexperienced halves including Brock Lamb, Jaelen Feeney and Jack Cogger.

Mullen is contracted until the end of 2018.