This has been touched on by myself and others in the middle of another thread about Kyle Cook. I thought I would move it over here for discussion. Here is my rationale for shopping Rey in return for a replacement for Kyle Cook.
One, a trade will bring us a higher caliber player than anyone the Bengals could pick up on waivers.
Two, Rey has proven he can start at MLB and OLB in the NFL. This gives him good value to teams who are still searching for a MLB and he will net a higher return than any backup or rookie offered by the Bengals.
Three, Rey is in the last year of his contract and has been injury prone. The injury issue is also why I would play him in the last preseason game. Show the league he is healthy.
Four, Burfict and Muckelroy have both proven in the preseason that they could be longterm solutions at the MLB position. They are younger, under contract and I believe have better instincts than Rey (especially Muck). There is also Skuta who can play MLB in a pinch, if necesary.
There seem to be no downsides to trading Rey right now and I think he gives the Bengals the best chance to get back a starting quality center.