Please take this list/information with a few handfuls of salt for a variety of reasons.
First off, it is compiled by former Bears GM Jerry Angelo, who for 12 years presided over an organization that is notorious for having quarterback problems.
Second, his QB ratings on a nine-point scale seem to be rather arbitrary in terms of the exact number. It's less like a complicated advanced metric and more like "how much did you like this movie?"
Third, he rates Philip Rivers a full two levels ahead of Tony Romo.
That said, these kinds of lists are FUN. And they speak ill of the Vikings' QB situation in 2013 since, well, this: Angelo ranks all three Vikings QBs last season (Christian Ponder, Matt Cassel and Josh Freeman) in the 5.5 to 5.9 point category. What does that mean? Well, here's the general description of QBs in that frame:
Can be an emergency starter. Does not have the mental make up or physical talent too perform as a consistent starter. He’s temporary relief, but not a long term solution.
Your 2013 Vikings! (And yes, we write that with full knowledge that we endorsed, nay begged, for the return of Matt Cassel in 2014).