Nowhere in that article does it say that the award is supposed to be for players who missed an entire season. That's just an article, written before this season, predicting that Manning will get it based on past winners.
Here's an article written by a voter that actually addresses the criteria:
Eagles' Michael Vick leads deep group of NFL comeback candidates - Don Banks - SI.com
Other writers (voters) have also made note, over the years, of the fact that the definition of a "comeback" has been purposefully left vague.
1. Don't try to move the goalposts now. You said I "PULLED IT OUT OF MY ASS" and I obviously didn't.
2. Good job on research. You still fail though because you referenced the wrong award. The AP has their own comeback player of the year award, but the recognized one is the Pro Football Weekly award. Don Banks is very clearly referring to the AP award
and in the article I put up he says several times that it's for missing the 2011 season, he lists all of the people who are on that list, then lists the exceptions because of the one time Joe Montana won.