He's not getting too much mention around here as a FA QB. The facts are Flacco won't hit the market, Alex Smith is a game manager at best, and Tavaris was horrendous in Minnesota for years. A 40 year old Favre put them in the NFC Championship game, while Tavaris couldn't average close to 200 yards per game through the air.
I would kick the tires on this. Get one of these QBs in the 2nd or 3rd. I like Manuel in the 3rd. Then if you are in a position to grab a guy next year you are free to do so. Worst case either Manuel or Campbell work out.