Passer rating is still a great way to tell how well a qb is actually playing. It's not the end all, be all. But I think it paints a pretty good picture of how their season is going. Here are the top 5 qb ratings so far:
1. Tom Brady - 123.3
2. Matt Ryan - 115.1
3. Dak Prescott - 108.6
4. Drew Brees - 106.4
5. Kirk Cousins - 101.4
Carr, Mariota, Big Ben, Stafford and Wilson are all in that 99.3-100.6 range. FYI.
Then you have to consider what the backup would do, if these guys were to go down. Then substract the (guessed at) difference, and decide their overall value added to the team.
Would the Pats be 8-2 under Garoppolo? For what it's worth, Jimmy had a 117.1 passer rating in his limited action this year. So.. I think that is a few marks against Brady being the unquestioned MVP, just because he is #1.
Matt Ryan should be on the short list. Imagine replacing him with Schaub, or Vick? That team would collapse. Also, remove Dak and we saw last year what the Cowboys look like without a true talented qb.. they sucked. They could not win a single game last year without Romo. Strong case for Dak here too.
Brees' chances are really hurt because of their record. And honestly because he does this every year. Kirk on the other hand is a true wildcard; it will depend entirely on how he finishes the season out. So far though, he has as of late played outstanding.
I think Elliott is the only non-qb that's in serious consideration, at this point. But I wouldn't count out someone like LeVeon Bell either, if the Steelers win out, or get close to it.
I would say all things being equal the race is very contingent on how the season finishes up, with Elliott being the slight frontrunner for MVP right now.