Knee affecting J.R. Smith's shot?

For all of the hot streaks that J.R. Smith has had as a pro and his outstanding 2012-13 campaign that led to a Sixth Man of the Year Award, he really isn't a very steady shooter. He has hit just 42.4 percent of his shots from the field as a pro, and he has posted a 42.2 FG% or worse in three of his past four seasons.