Jarrod Mullen could miss up to four months of NRL action after Newcastle confirmed the five-eighth has torn his hamstring off the bone in a devastating blow to the Knights’ premiership hopes.

Mullen will consult with a surgeon on Monday to find out what his recovery time will be, but it’s likely the playmaker will miss the majority of the season.

On the same morning the Knights re-signed promising halfback Tyrone Roberts to a new two-year deal, the club confirmed Mullen had suffered a “hamstring avulsion” during the Auckland Nines tournament last weekend.

At the time, Mullen went to ground as if he’d been shot by a sniper, clutching the back of his leg.

The 26-year-old possesses one of the best kicking boots in the game and after an outstanding end to 2013, would have been on the radar for a return to State of Origin with the Blues this season.

Fresh from being handed a new contract, it would seem 22-year-old Roberts is set for a major jump in responsibilities.

Roberts played all 27 matches last season and is seen as a future leader at the Knights.

“Tyrone is an outstanding young man and has a wonderful future ahead of him,” said coach Wayne Bennett.

“It has been pleasing to see him grow in confidence and we are delighted he has re-signed with the club.

“Tyrone is one of our key young players who will be a long-term player at the Knights.”

Newcastle may consider moving Kurt Gidley from hooker to the halves to compensate for Mullen’s loss, but their other option is to give a start to former Canberra half Michael Dobson.

Gidley has been training to permanently take over from Danny Buderus at No.9, but is an experienced ball-player who could provide good support for Roberts.

Dobson will get his chance this weekend in a trial against Canberra in Tamworth, after being named in a 22-man Knights squad.

Mullen joins the list of serious injury worries to come out of the inaugural Nines, headed by an ACL injury to North Queensland’s Lachlan Coote.