Golden Knights’ forward Valentin Zykov was suspended for 20 games, without pay, for violating the terms of the NHL and NHLPA’s performance enhancing substances program, the league announced Thursday morning.



Zykov’s agent Rolland Hedges told The Athletic his client was taking an “over the counter supplement that has been approved,” and he was unaware of any banned substances in the supplement.



According to Golden Knights president of hockey operations George McPhee, Zykov has been knowingly using that supplement for the past four years.



“We found out yesterday,” McPhee said. “We were completely in the dark until that point. Obviously this takes a while to percolate, but we seem to be the last to know. I had a conversation with Zykov and a conversation with his agent.



“We have our sports performance department (which) is elite, and we are really exhaustive and comprehensive in educating our players...