It wasn't because I thought Damaso Marte and Xavier Nady wouldn't help the team (which they largely haven't), or that Jeff Karstens, Ross Ohlendorf or Dan McCutchen would turn into anything special. It was all about Jose Tabata.
He was among our top prospects and even among the top in baseball. In the midst of last year, he was playing poorly, no question about it. He wasn't hitting much (.248/.320/.310), was dogging it in the outfield, had some injuries, and even went AWOL one time. But everyone knew he had the talent and approach to be a great hitter, and the Yankees sold low on him.
The rest of that year, Tabata hit .348/.402/.562 with Double-A Altoona. And this year, between Double and Triple-A, the 20-year-old hit .307/.372/.422. The power that scouts expected would come seems to finally be appearing.
This wasn't like trading a 23-year-old with promise; Tabata was a teenager with immense promise who was already in Double-A, which in and of itself is impressive. Pittsburgh has even been playing him a bit in centerfield, which will increase his value. The Yankees were playing him exclusively in rightfield.
Tabata will play in the Arizona Fall League, where teams' top prospects often go. Don't be surprised if he gets promoted to Pittsburgh early next year.
Then if you really want to suffer, think about how much time Marte and Nady have missed. In more than a full season since the trade, they've played in a combined 102 games. Nady will be a free agent after the season while Marte was signed to a three-year, $12 million deal. Would anyone not rather have Tabata (and the three other pitchers)?