My take means nothing to anyone, but I do think it warrants a read for people who own Bell in a Dynasty League.
I only owned him in one league. A Dynasty League I have won before. This offseason, after they tagged him, I traded Bell. People in the league said I didn't get enough for him; Two number 1's in the rookie draft (likely to be later first round selections), Calvin Ridley and Eric Ebron. Ridley isn't going to do anything in 2018, but that's not what I wanted him for. Ebron just may surprise some folks under Reich, a Head Coach who knows how to use his TE's. That said, I had other reasons to dump Bell.
One - I truly do not believe he will be even 80% as effective outside of Pittsburgh. I believe his rushing totals will drop in a big way. In his Division, he has had the luxury of facing Cleveland twice per season while they were the worst team in football, while Baltimore and Cincy (sometimes) utilize a 3-4 that benefits Bell. The Steelers have a good offensive line, which typically does well when facing a 3-4 front. Take Bell and put him in another division, where he is facing 4-3 lines, do you believe he will still be able to stutter step behind the O-Line the way he does currently. I don't think he will. How many times have you seen him patiently wait while a lineman opens a hole for him? You can't do that with a mediocre line. The team able to sign him for what he wants is going to have some holes....
Two - I see his Agent's viewpoint on holding him out. He has a lot of mileage on his legs already. How long will he last with a new team and an inferior offensive line (assumption on my end)? I can't imagine a team is going to sign him, then not run him completely into the ground. With so many touches on those legs already, do you think he can last a full season?
Three - History shows that RB's changing teams typically doesn't work out well for anyone. Injury has played a role in some of that, but sometimes a different scheme kills the value the RB had prior. Would Bell be as valuable without double coverage going to Antonio Brown on each play? How about the fact the defenses he's faced have always had a deep threat on the other side of Brown (Williams, Bryant, Smith-Schuster and possibly Williams now)? If he went to a team with inferior WR's (almost anywhere else), will he face an extra defender in the box? Likely so.
To me, three strikes is enough to trade away a player, even of his caliber. You may be stuck waiting until he shows up to play before you can trade him now, but when he does, I would say to let him go. He isn't playing in Pittsburgh next season. The only teams with the salary cap room to sign him have horrible offensive lines (think Buffalo). He isn't the style of runner that is going to be a good fit with the 49'ers and Cleveland has 3 RB's now. The Colts will have the salary cap room, but do you see them bringing in Bell when they have holes all over the roster? Trade him when you can and you will still walk away with quite the haul, especially if you do so the week of the trade deadline when owners are willing to pay more.