Lance Berkman is a Yankee. Just sit back and think about where you were in September 1999, when he came up. And think about where you are now. That's a lot of my life tied up when Lance was an Astro.
Granted, he may be back next year, and he could feasibly change his mind in the next 20 hours, but he probably won't.
Joel Sherman explains the 24-hour window and also explains why Berkman won't be negating this deal:
A person involved in the negotiations for this trade said Berkman was elated to rejoin his pal, Andy Pettitte, with the Yankees and that “Lance was viewing this as a once-in-a-lifetime opportunity to play with the Yankees.”
Do you see the difference between the organizations? Lance, a lifer with the Astros, native Texan, Rice alum (etc.) is elated to go join the Yankees. J.A. Happ, taking the field in front of a team without Berkman or Pence, and featuring Carlos Lee and Pedro Feliz, wept at leaving "the only place he's ever known."
The Astros are on the right path, but honestly? It's sad how bad things had become.