Martellus Bennett Crushes Workout, I'm Coming Back W/ Jason Witten!!

[[tmz:video id="1_m7i0fhkl"]] IS MARTY B COMING BACK TO BIG D?!?!?!? Probably not ... but the ex-Cowboys TE joked during a workout Thursday that he MIGHT be -- and the clip is funny as hell. Of course, Jason Witten just ACTUALLY came out of retirement to…