NRL clubs may face drugs probe Stood down ... Dean Robinson. AN INVESTIGATION into the use of supplements by Essendon players is set to be expanded beyond AFL, with Fairfax Media told NRL clubs are also likely to face scrutiny. The Bombers called in the Australian Sports Anti-Doping Authority to look into supplements given to their players but it is understood the investigation will be broadened beyond the AFL club in coming days. It is understood up to 18 Essendon players are under scrutiny but they may be the tip of the iceberg as some officials believe the use of the supplement is widespread in the AFL and NRL. Any athlete found to have taken performance-enhancing substances - whether knowingly or not - faces a two-year ban. While Essendon officials have not fully outlined what triggered their concerns, it is believed players were administered peptides via injections at a premises away from the club last year. Peptides can be used to stimulate the production of naturally occurring hormones, increase muscle growth and strength, and increase the production of red blood cells to improve the blood's ability to carry oxygen. The supplements used by Essendon have been described as being "on the edge," and it has been alleged players were asked to sign waiver forms before receiving an injection. The Bombers have sacked sports science guru Steve Dank and stood down high-performance manager Dean Robinson, both of whom worked for Manly. There is no suggestion of any wrongdoing by either. Dank, employed by the Sea Eagles from 2005 until 2010, was also briefly involved with Cronulla in 2011 but left after a clash with club doctor Dave Givney over players using the blood-thinning tablet Warfarin. He came to prominence in 2008 after Fairfax Media revealed Manly players were being injected with calves' blood to hasten their recovery from injury. Under coach Des Hasler, the Sea Eagles were pioneers of sports science and tried to keep their practices top secret but the use of Actovegin - a product containing calves' blood - leaked when a former player told staff at his new club about it. Former Manly captain Matt Orford confirmed on Wednesday he had calves' blood injected into his muscle tissue to treat a groin injury in a bid to keep him on the field during the club's 2008 premiership-winning season, but said it "failed." A source close to Hasler said while the now Canterbury coach was prepared to push the boundaries, he is a stickler for rules and a control freak who would have ensured his players were not at risk of taking illegal substances. Manly officials told Fairfax Media after the scandal broke on Tuesday they had no concerns about the use of supplements by players while Dank was with the club, and football manager Steve Gigg said on Wednesday they would welcome any investigation. "We would be open to any sort of inquiry," Gigg said. Steve was good for our place for a certain amount of time. He was only a part-time consultant, he was looking for full-time work and we couldn't offer that so he moved on. Former ASADA boss Richard Ings said the Sea Eagles had come under scrutiny during Dank's five years at the club and while the physiologist had never been found to have done anything wrong, it was clear he "pushed the boundaries." "This was an era where there was lots of discussion and media coverage about substances like Actovegin and calves' blood treatment," Ings told FoxSports. It did highlight tendencies by some clubs to push the boundaries and take risks. While careful not to accuse Dank of any wrongdoing, Cronulla coach Shane Flanagan praised his club's medical and training staff for ending the Sharks' association with him after just a few months. "I don't want to criticise other clubs by coming out and saying we were the smart ones but we did escape before he got his claws in," Flanagan told Sportal. We've got some things in place with our doctor and physio and they're across the medical side of things and the use of supplements. They take control of that - that's the way we run. Robinson spent two years at Manly before joining Geelong in 2007 and was considered an integral part of the AFL club's premiership success in 2008 - the same season the Sea Eagles beat Melbourne 40-0 in the NRL grand final. St George Illawarra high-performance manager Andrew Gray said the Dragons had every supplement from their US supplier independently tested before being used.