Reid has failed to overcome an adductor injury he incurred at training, ruling him out of tonight's do-or-die contest at Hindmarsh Stadium.

Reds ACL Head Coach Joe Mullen yesterday admitted Reid was ‘doubtful' for the match, and following the squad's final training session last night, the 30 year old conceded the injury would force him to watch the game from the stands.

The injury is the latest in a string of setbacks for the unlucky Reds midfield general, who was limited to just two appearances in the Champions League Group Stage and only eight A-League games last season.

Reid combined with Adam Griffiths in an impressive central midfield pairing in United's last outing against Shandong Luneng, but just as he appeared to have put his injury riddled past six months behind him, the two time NSL championship winner will again miss out.

"I'm devastated to be missing this game. It's a massive game for the club and the players and I'd love to be out there," Reid said.

"Unfortunately the adductor has not recovered in time for the most important game for the club this season."