In this play from week 6 there was also a Patriots defensive player in the offensive backfield, linebacker Junior Seau who was lined up just behind the QB. Seau was in front of fullback Heath Evans who was in the HB spot. At the snap, Brady fakes the handoff to Evans, and he and Seau head for the right C gap (between the tackle and tight end). This draws three of the Cowboys' linebackers towards that hole.
Meanwhile, TE Kyle Brady has chipped one of the Cowboys' linebackers and released into the back of the end zone. Since the Cowboys were so concerned with Vrabel, both the SS and a LB had drifted over to cover him. That left Kyle Brady wide open.
In other words, a linebacker acted as a decoy for a tight end. Play-action pass from Brady to Brady and New England took over the lead and held it for the rest of the game.