Newcastle playmaker Jarrod Mullen has been provisionally suspended by the NRL for breaching anti-doping rules after testing positive to an anabolic steroid.

The Knights and NRL announced the news on Tuesday afternoon, with Mullen returning a positive sample to Drostanolone in an out-of-season test in late November.

Under the NRL’s anti-doping policy, Mullen has the opportunity to have his B sample analysed, however he has been prohibited from playing during the suspension.

“The club is obviously extremely disappointed,” CEO Matt Gidley said in a statement.

“The club has a strict governance program, the players are regularly educated and fully aware of the consequences of going outside our governance guidelines.

“From here, there is a formal process we need to follow under the guidelines. We need to respect the process and in the interim the club will continue to monitor Jarrod’s welfare.”

The Australian Sports Anti-Doping Authority said it had completed the test on November 29.

“ASADA undertakes a comprehensive anti-doping program to ensure the integrity of the NRL competition,” ASADA said in a statement.