2 Thoughts:
1) Injury. Nuff Said. (Especially with Lee's history of ab strains)
2) NYY, who are in a tight race for division, finalize the deal in order to "give" themselves another win. If they get this done today instead of tomorrow, they avoid Lee starting against them, and seeing as SEA sucks biggins without him, essentially "give" NYY a win. And in a division like the AL East, how much do you think the Yanks value each and every win?!?!
If I asked you "What team would make a move just before their aquisition target was scheduled to start against them, making an underhanded and $$ move that "buys" them wins??"
You would say, without skipping a beat: "The Yankees"
I agree with you