The classic "He was injured" response to a player's poor form. He's a decent winger playing at a club too big for him. Spurs / Liverpool is his level. I'm unsure how Zaha will adapt to the prem in his first season but I'd much rather see him have a go than Ashley Young.
He was injured though. I don't care if it's a 'classic', if a player is injured then don't judge him as if he's fully fit.
If you don't think him good enough in spite of his injuries then how can you explain his excellent form when fully fit?