roethlispuker is the best QB that the steelers have, therefore he will start when he comes back, period.
Even if they're 4-0?
If the Steelers are 4-0 with Dixon I'm pretty sure the coaching staff would realize that they also would be 4-0 with Ben. You play your best players period. Dixon is the 3rd string qb who is only playing because Ben is suspended and Leftwich is hurt. Leftwich might be back for game 3 anyways.
But see, in this hypothetical, they aren't 4-0 with Ben. They're 4-0 with Dixon. That would be the reality. And I think a 4-0 team would rally behind the young guy to keep the job over the guy with a lot of problems who let the team down by getting himself into trouble. I think the Steelers would LOVE to see Dixon claim the job, win all his games and never let it go. It would make getting rid of Ben a lot easier. He's a headache and a black eye for the team. He's also a very good quarterback who plays well under pressure. So they need someone special to replace him, and they'd be very happy if Dixon was that guy.
Now, don't get me wrong. I don't think it's going to happen here. But I don't think Tomlin is keeping the spot open for Ben no matter what happens. I think he wants to leave that door open just in case. I also think Dixon knows that winning four games earns him a fifth game, and so on.
Again, I don't really see it happening. But if the team goes 4-0 I don't think you see Ben behind center in week six after the bye.