That's an idiotic answer. We're not even in May yet, the draft ended yesterday, the minicamps are not even underway, this is not a situation that would be happening now, but rather something the team could explore in August.
Brady is exactly that. In the end the Pats kept him because Belichick saw something, but how many teams keep 4 QBs for a full year ? How many other teams would have kept him ?
Otherwise : Mark Brunell, who was buried on the Packers depth chart, was traded for a 3rd because he couldn't get past Detmer. Kurt Warner, who didn't make the Packers because he couldn't beat Favre, Brunell and Detmer, got cut and could have been available for a trade in the way mgteich envision. Jeff Blake was cut from the Jets before having a couple of good seasons with the Bengals. John Unitas, cut from the Steelers. Heck, we just lost the Super Bowl to Nick Foles, who was cut by the Rams and the Chiefs. That's just on top of my head...