It's probably the latter. I'm sure he must have a chance if he's in there but it would seem silly to take any sort of risk, even if scans say there isn't anything there. I'd probably go as far as to rest him until we go to HKR on the 11th April now. With us having Salford beforehand and then a break when the cup is on, it will give him plenty of time to get some rest in and some work in the gym and it will also allow Farrimond a couple of games, which I think he needs. 

Definitely would give Field a few weeks off even in the scan comes back with nothing

Kicking is going to be an issue with Keighran out for a while

Harry Smith is more than capable of kicking goals

Is it the case that only players in the 21 can be selected for the match day team, ie if the don't put him in the squad then there is no way he could play?

Sticking him in the squad to keep Leeds guessing doesn't feel like something Peet would do. Really isn't worth the risk though with a winnable game against Salford and then a week off coming up. But the coach is paid to make those calls.