A fitness test tomorrow morning will determine the availability of NSW interchange utility Ben Hornby for Wednesday night's State of Origin decider.

Hornby is battling a groin injury suffered during training yesterday, with scans revealing only a minor strain. NSW officials will wait to see how Hornby pulls up following tomorrow's session before making a decision on whether to bring a shadow player into the squad.

The Blues were given the afternoon off after spending the morning signing autographs during a promotional visit at a Melbourne shopping centre. The Telstra Dome clash is already a sellout.