Housler can't catch, that's the biggest reason why he's struggled in Arizona. He struggles to extend away from his body, which is a critical skill for a TE since they rarely are able to create the sort of separation where they can let passes get into their body.
Remember 2010 when Roddy was leading the league in drops? He had like 15 that year on 115 catchable passes (according to Pro Football Focus). That's a drop rate of 13.04%.
Housler for his career, has dropped 14 on 105 catchable passes, a drop rate of 13.3%.
So take Roddy's worst season as far as his hands go, and that's Housler's average season.
Do you think its a concentration issue or he suffers from Harry Douglass-itis which prevents him from catching passes in traffic. Even if he struggles in that area, he could still be a capable target in the seam off size and speed alone.