He's paired with Bargnani, that's tough for a rookie as he have to defend against two players now. Starting with Lowry doesn't help either as he ignores JV being open under the basket and waving hands like crazy, well this accounts for almost all the team, Raptors
are not known for passing much..
I think it would work better for him to start from the bench together with Calderon. JC doesn't have a tendency to go 1 against 5 like Lowry, passes the ball more often and his play style overall better for JV. In 2nd unit with say Ed instead of Bargnani
there would be less gaps left and so on. Casey should try that few games to see how it goes, I'm sure it would just give JV more confidence.