A home-grown product who was often the face of the club at community events, the clean-cut Mullen was among the most popular players at the Knights with dyed-in-the-wool supporters. 

Just last month, Mullen rushed to visit fan Elissa Jack, who underwent surgery to remove a brain tumour, in hospital.

But after asking why Mullen had allegedly taken an illegal, performance-enhancing drug, many Newcastle supporters, unfairly or not, wanted to know what his provisional ban means for the club’s roster. 

Hungry for success after consecutive wooden spoons and a season featuring just one victory, the Newcastle faithful are desperate for a winning team.

Mullen was among the Knights’ highest-paid players, reportedly on more than $700,000 a year, and on contract until the end of 2018.

While his wage is not uncommon for top-line halves in the NRL, Mullen has made only 14 and 10 NRL appearances over the past two seasons because of injuries, frustrating long-suffering supporters. 

His latest setback came in late November when he aggravated his surgically repaired hamstring at training.

He told the Newcastle Herald on November 29 – the day he submitted the positive sample – that “if it keeps going, it will be pretty hard to get back”.

In August, Mullen rubbished reports the Knights were trying to offload him as part of a clean-out to free up salary cap money.

“I definitely don’t want to go anywhere,” he said.

Tuesday’s bombshell, though, has seemingly opened the door for the Knights to recruit new talent.

When asked if the club would pay Mullen while he was provisionally suspended, Knights chief executive Matt Gidley said on Tuesday: “I’m not going to discuss that at the moment.”

Gidley also would not comment on whether Mullen’s wage would continue to count as part of the club’s salary cap this season.

However, Mullen’s breach, if confirmed with a positive B-sample, will likely bring a long suspension and end his contract at the Knights.

Coach Nathan Brown, preparing for his second season at the helm, has already shown his desire to rebuild the club with young talent, signing 18-year-old North Queensland fullback Kalyn Ponga to a multimillion-dollar, four-year deal starting in 2018.

The Knights have also not hidden their interest in attracting the likes of Cronulla’s Jack Bird, who is off contract after this season.

Newcastle have already brokered deals this pre-season to release out-of-favour former Test winger Aku Uate to Manly in return for utility forward Jamie Buhrer as well as fullback Jake Mamo to Huddersfield in exchange for robust centre Joe Wardle.

Prop Korbin Sims could soon join the list of released players after reportedly showing interest in reuniting with former Knights coach Wayne Bennett at Brisbane. 

Rugby League Week reported earlier on Tuesday that South Sydney were also keen to sign Sims. 

Ken Sio, Rory Kostjasyn, Jacob Gagan and Josh Starling are recent additions to Brown’s squad, and he had not closed the door to more recruits for 2017.

With Mullen’s shock ban, the Knights will turn to the likes of Brock Lamb, Jack Cogger, Will Pearsall and Jaelen Feeney to fill the breach in the short-term.

Members of the young line-up were already set for more game time this year given Brown’s plan to experiment with Mullen at dummy-half. 

In the long-term, Brown will likely now have even more bargaining power to add the likes of Bird to that list.