Queensland Maroons' Matt Gillett in doubt for State of Origin III due to injury

Queensland's Matt Gillett appears in doubt for Wednesday's State of Origin series decider in Sydney after suffering a groin injury at training.

Queensland official Darren Lockyer revealed Gillett had been injured at training on Friday and indicated 18th man Ethan Lowe was on standby.

"He's had a groin strain and Lowe is 18th man. I am not sure when (coach Kevin Walters) will make a call if Gillo plays," he said on Nine's Sunday Footy Show.