St Helens Wolf:
With this level of uncertainty over so many players it would seem strange to leave Wrench out of the 21 if he was fit. Especially as he needs game time.
It could just be that they are managing his return and being cautious. That would be understandable. Being fit to play again is one thing, but it doesn't necessarily mean that you are instantly back to 100% and ready to play in every game. Of course, I am only guessing as to the reason for his absence, as neither the club nor the WG saw fit to shed any light on it in their squad announcement stories.