ESPN.com published its NFL QB rankings by "tiers," with Mike Sando compiling the list with the help of voting by 50 league insiders — and with the 32 projected starters divided into four tiers.

Four QBs are in Tier 1: Aaron Rodgers, Tom Brady, Drew Brees and Ben Roethlisberger. That seems about right, though I might drop Big Ben into Tier 2 and just keep that top three.

After that it gets interesting and relevant to the Vikings. There's a cluster of 10 quarterbacks in Tier 2, but it does not have Vikings QB Kirk Cousins, who checks in at No. 15 overall as the first QB in Tier 3.

If Cousins can be a Tier 2 QB, carrying the Vikings sometimes and making special plays, the Vikings are legitimate contenders.

If Cousins plays more like a Tier 3 QB, relying more heavily on the run game and defense, the Vikings are still a playoff team. But their margin for error is diminished, as are their Super Bowl chances.

Read Michael Rand's blog at startribune.com/randball. michael.rand@startribune.com.