I wouldn't draw any conclusions based on what we've seen so far. Vaughn has mostly been in the game when we've had a big lead and the defense expects us to try to run the ball. He's also been in when some of our best linemen have been on the sidelines because it's a blowout. Circumstances always play a role.
I believe one of the few times he's gotten the ball in a competitive game (before the late third of fourth quarter with the team having an insurmountable lead), he had a 13-yard run followed by a 11-yard screen pass. That was against the Jets, so I could be wrong about it being competitive at the time, but I do believe it came with the entire offense still out there and when we weren't just trying to run out the clock.