It is, unfortunately for him I don’t think it matters what he does with the bat he won’t start the first game in the ashes
He's opening mate.
More seriously, it's difficult to know how that lower order will be arranged. I assume the top four will be the same and Buttler and Stokes will both slot in at 5 and 6:
so
7: Bairstow and 11 Anderson are pretty nailed on. Archer and Wood are injured so that gives you 8,9,10 for three of Leach, Ali, Broad, Curran, Stone, Woakes. I'd assume that Stone will miss out and that Broad probably won't so Leach, Ali, Woakes, Curran. I'd imagine they'd go for Woakes, but even if they don't then Curran is a very handy batsman who is more than good enough to bat at 8.
All of which is a pretty long winded way of saying that I imagine who gets picked as a spinner can come down to who the better spinner is because there's plenty of batting there anyway (and Ali is in woeful form with the bat) and that is probably Leach.