Yes, each season 10 games in, there will be a couple of teams skewed downward by a key injury.
But where that injured team is in the standings after game #10, still gives you a good idea of how good the team will be that season, even after the key player returns. If they suck without him, they won't move way up in the standings after he's back. Their problem is elsewhere in their roster or coaching.
(Vonleh is not a key player anyway. We have only one key player, Lillard, because of the odd Stotts system preventing guards from playing defense, and because Olshey refuses roster balance by trading the overrated McCollum for a star scoring Small Forward.)