I wonder whether Evans may be going through some of the same pouting that Cousins is going through: prior to the trade deadline, he had the "carrot" of New Orleans trying to move Gordon, and was crushing as the sixth man. After the deadline passing, and realizing that he's going to have to continue to play behind Gordon (a player whom, despite being a better shooter, is probably not as good overall), and I wonder if he may have just said "**** it."
Seriously, though, he was really hit hard by Anderson going down. I personally loathe the concept of the "stretch 4" (in fact, I think that Don Nelson ruined basketball, because of it), but if there's any player in the league who needs to play alongside a stretch 4 to maximize his abilities, it's Tyreke Evans. You can get away with not being about to shoot, if you have a teammate who can pull a shot blocker away from the paint. Without Anderson, Evans doesn't have that, and it's shows.