The Astros biggest need, in my estimation, is a third baseman. Matt Dominguez now has 1300+ major league plate appearances with a .275 on base percentage, and is trending down. There are several prospects in the system that could take that spot, including Colin Moran and Rio Ruiz, but they are not ready yet, and are not sure things. The free agent market is one option, but could require a 5 or 6 year commitment to a declining asset.
Meanwhile, in New York, there is a team with a 3rd Baseman, who, by all accounts, they are done with. That's right, I'm talking about Alex Rodriguez. I know what you are thinking. He's overpaid, he's declining, he's a cheater, he once posed for a picture kissing himself in the mirror. All those things are true, and are the reason why he might be obtainable for very little. He is also, almost certainly, a legitimate upgrade at third. A-Rod has never posted a wRC+ under 113, and his full season low on base percentage is .348. Even in 2013, he put up .5 WAR in just 44 games. There is no guarantee he could produce those numbers after a year off at 39, but the bar to upgrade 3rd base is very low. I think its safe to assume he could be a legitimate 2 win upgrade over what the Astros had at 3rd last year.
This might not be a safe assumption, but assume the Astros would be able to absorb a large chunk of A-rod's contract. Right now, he's due to be paid 20 million a year for the next three years. Lets say the Astros take on 15 million of that. In that event, the Yankees might practically give him away. The Astros' surplus of catchers matches up with the Yankees' need. They have Brian McCann, but just lost their backup to Pittsburgh. Meanwhile, Carlos Corporan put up another fine season, and has proven himself to be a worthy backup. Would Carlos Corporan for Alex Rodriguez be something the Yankees would consider? I'm not sure, but it actually makes a lot of sense for both sides.
The Astros would have an immediate upgrade at 3rd, and the Yankees would be freed of a player they no longer desire, plus getting a nice backup catcher. The three year commitment is probably better than the Astros could do in the free agent market, and in the event one of the Ruiz or Moran is ready earlier, Rodriguez could easily move to a 1st/3rd/DH rotation.