6 games under .500 in May is not.
Well, even though I am definitely not a fan of the Yankees, I am a fan of a different team who found themselves in a similar situation last year...
2006 AL Central Champion MN Twinsas of May 30th, 2006 - 23-28 (4th place, 11.5 games back)
at the end of the year - 96-66 (1st place)
So yeah, I agree that 5 or 6 games below .500 (and 10+ games out of first) in late May is no big deal...

Baseball is funny like that. Teams get hot and cold at different times of the year, it's really too early to write them off just yet. Now, if the Yankees are still below .500 after the All-Star break, we can start talking bad about them.