we lost to them.
Denver lost to #14 7-5 Penn State 15-10
So they would have the worst loss - I'm guessing that and the rankings are the reasoning for the seeding.
Inside Lax and Lax Magazine have us #1
Denver is #2 and #3
That being said, it appears that the 2 best teams are ND and Denver, so the thing that matters most - being in the opposite bracket from them. Then take care of business.