The NFL isn't for everyone. Players are quickly shipped in and out either because they don't have the talent, or they'd rather play in another league to get themselves fully seasoned.
NFL Europe, the CFL and UFL have all provided homes for "misfit" football players in the past. Some examples are Kurt Warner (Europe), Jake Delhomme (Europe) and Ricky Williams (CFL).
While the surrounding players in these different leagues aren't of the same caliber, getting starts and extra reps in is what some past or former NFL players did with their change of scenery.
With the draft coming up in exactly three weeks, which popular collegiate players won't be seeing time with the NFL, but time with a league like the UFL?