Yes, actually, much as I don't like it.
If he's lost a step it's not in foot speed, it's in conditioning, because the problem right now isn't him being slow it's him staying upright and not closing out on opportunities that aren't 100% direct scoring chances. He doesn't get to enough 50/50 pucks or make it hard for defenders in the defensive zone when he's the closest guy to prevent a clear. And to be fair that's always been him a little bit, but it's more pronounced right now and it takes an extra second for him to commit to the times he needs to do it.
That means he's not creating many burst opportunities unless the puck and goal are both in front of him, but when those situations arise he doesn't look tangibly slower than last year. He's not even finishing checks that the Ovechkin we know would do just to prove a point, especially when they're losing even when they're there.
That's not being slow because he's not late at all, it's just him not doing it.
EDIT: If he's not loafing I think between this and his general reluctance to really fire slapshots he might be working through something