I detailed a bunch of reasons why Chris Johnson is overrated
here in a different thread. He's been a mediocre (at best) boom-bust volume rusher since his breakout 2009 season.
I didn't even get into success rate in that post, which is a pretty important stat to look at when judging a RB. CJ has a career success rate of 37.4%. He's never reached even 40% once in his career. That's not good for any RB.
Certainly not good for someone who considers himself to be one of the best running backs in the league. I mean, he's clearly not, but he thinks he is. Which is part of the problem with him. He's always been a boom-bust guy (which explains the low success rates throughout his career) but the booms don't come as often anymore and the busts are pretty plentiful.
Let him be someone else's problem. You can find any number of RBs who will give you better production at a lower cost, and without the associated headaches CJ brings with him.