"We want to win the Premiership title and have come off three games in a week while Bath had a gruelling loss to Gloucester last weekend."
Rees was left out of Wasps' bonus-point win at Leeds, which took them into second place, and he believes the rest has been vital.
"I felt good in the team meeting before the Leeds game and then when I went out on to the pitch for the warm-up I could hardly put one leg in front of the other," he said. "I realised taking a break was the best option but now I am raring to go."
Paul Sackey, the England wing, will be given until the last possible moment to declare himself fit after injuring a medial ligament helping Wasps defeat Leeds. Josh Lewsey would take over on the wing if Sackey is rested.
Wasps expect to have prop Pat Barnard fit to appear in the No3 jersey in a team that have made a typically strong finish to the season.
"We always perform better when our backs are against the wall," said Fraser Waters, the veteran England and Wasps centre. "We haven't won the Premiership title for a couple of years and want it back."
Bath hope to have England front-row forwards Matt Stevens and Lee Mears fit to play and pugnacious lock Danny Grewcock will have a point to prove against Tom Palmer, who has been chosen ahead of the Bath man for the New Zealand tour.
Another exciting head-to-head sees Danny Cipriani facing Olly Barkely, the player who is likely to be the Wasps No10's inside-centre in the England team against the All Blacks.
