In Jason Cole's latest, which examines players trades, compensation and all that jazz, he quotes Michael Lombardi regarding Chad Johnson:
“Do you think anybody is giving up a first and a third for [Cincinnati wide receiver] Chad Johnson now,” Lombardi said. “No, because the perception is that Chad is declining. Everybody looks at this numbers and says, ‘He only averaged 10 yards a catch and his longest was 25 yards last year’ and thinks he’s close to being done. They don’t look at the tape and find out that the guy is getting open still, the Bengals just couldn’t get him the ball for whatever reason."
Well, when you're open with right when the quarterback is running for his life (ala Ryan Fitzpatrick), it really doesn't mean much.
So why the perception?
“They don’t call a former coach who was on the Bengals staff last year and find out what was going on in practice and what was the team really able to do. That’s why they don’t really find out and then judge for themselves.”
The main point here is that there's a perception that he's declining. But since potential trade suitors can't get an accurate assessment of Chad's talents right now, and why the "Bengals just couldn't get him the ball", the perception remains the same. And since that perception doesn't seem likely to change, it'll be difficult to move Chad on the reported first and third round picks that the Bengals demand.