Tate was expected to return from an ankle injury but injured his Achilles tendon during the week and dropped out of the side this morning. Utility Greg Eastwood has been called into the Broncos squad and will make the trip to Sydney later today.
Brisbane had another injury scare this morning when centre Justin Hodges quit training early with an ankle problem.
Marshall dislocated his shoulder against North Queensland on Friday night, just five games after having it repaired with reconstructive surgery over the summer. The gifted playmaker, who has now suffered five shoulder dislocations in his career, said Sheens' input would play a part in his decision.