Dynasty 1QB full PPR league.
I had Big Ben and Teddy Brigdewater as QBs (don’t ask, took the team over in a terrible state a year ago). Got Trey Lance in the rookie draft, so only need to keep one of them as a backup.
Whom would you cut - Big Ben or Teddy B?
I am answering this with a cringe: Ben.
Teddy just doesn’t have any upside. We saw him in Carolina last year, and he was meh.
At least with Ben, there is some potential for early game success, which you’ll need until Trey is starting. It looks like the 49ers are going with Garoppolo to start the season (idiots!).
Cut Teddy.
I actually thought this would be a no-brainer. But surprisingly enough, Teddy’s fantasy production last year wasn’t much lower than Big Ben’s, even though the Steelers were a much pass-heavier offense.
And Teddy has much better weapons at his disposal this year.
Last year, the Panthers ranked 6th in terms of completion rate, whereas Denver ranked 31st. If Teddy manages to even remotely pair his 2020 efficiency with Denver’s passing volume, he could be a very solid RB2 this year.
Still, that’s a lot of "if"s. And Big Ben certainly offers a job security that Teddy doesn’t have.
I’m leaning towards keeping Ben, too, but not without doubt. Hence this thread. 
Teddy’s weapons in Carolina weren’t bad. He had D.J. Moore, Robby Anderson, and Mike Davis. Denver is a slightly better situation, but it ain’t Dallas.
I am just remembering Ben’s early season success last year, and seeing that as your cover until Trey becomes “the guy” in SF.