Israel Folau will miss the Waratahs' final round clash with the Reds after failing to recover from a corked thigh.

The dual international was in doubt as early as Monday but was given every chance to recover, with a decision on his fitness made as late as Thursday morning.

The Waratahs have already secured a first ever minor premiership and, with little to gain - aside from match fitness - by playing Folau, it was decided he would sit out the match.

Cam Crawford comes into the starting side at fullback, with the rest of the back line unchanged.