I'd probably take the opposite approach and start him as number 1 as he'd be coming in off the back of an amazing season at Burnley and getting a big move so you'd expect his confidence to be sky high and we'd still have a brilliant keeper to fall back on if his confidence did drop. That's obviously reliant on Pope being happy to stay on as number 2, which he might not be as he's still one of the top keepers in the league.
Either way I think Trafford's a good signing