Chiefs Trade for Cassel, Vrabel

The Chiefs made the biggest splash of offseason thus far by landing Matt Cassel and Mike Vrabel from the Patriots for just a second round pick (34th overall). It would seem as though Vrabel is just a throw-in, considering that the Pats were looking for a 2nd-round pick for Cassel originally. But if he's really only throw-in material at this point in his career, wouldn't Scott Pioli be aware of this?

There were originally reports supporting the Patriots basically giving away Vrabel due to the fact that there was no market for Cassel. But if recent reports that the Broncos were interested are true, then what's the Pats excuse?

My guess: the Pats are ready to start a new era on defense and Vrabel's starting job was in jeopardy. Belichick was willing to part with him and figured why not do both Vrabel and Pioli a favor by sending him to KC where he can still be an impact player and help the Chiefs transition into a 3-4 defense.