9 out of the 10 teams with a QB that had a 90+ passer rating went to the playoffs last year. The last time Miami had a passer with a 90+ rating was Pennington in '08. That is also the last time they were in the playoffs.
I made a Fanpost almost a year ago titled: "What Should Be Expected From A Dolphins QB". Basically it boiled down to a 90+ passer rating, 8 more TD's than INT's, and 62% completions.