Melky is not a bad player; he's certainly useful, but his time as a good value was dwindling. He's averaged around one WAR per season since he broke into the big leagues and is pretty much a known quantity at this point The fans have projected him for 1.4 WAR in 2010. It's unlikely that he significantly improves his skill set in the upcoming years; sure, it could happen, but it is unlikely.Cabrera is under team control for three more seasons but is entering his second year of arbitration right now. The recently converted outfielder is known for ability to light up the radar gun. This year in the Arizona Fall League, Dunn topped out at 96.7. 
As a lefty with that kind of arm, he'll get an unlimited number of chances. There are two things that hold him back from being a top prospect, though First, he's a reliever, which limits his ceiling. Second, the walks.Mike Dunn's control is very iffy, and it results in a ton of walks In the AFL, he showed just how tantalizing this can be. In only 10.1 innings, he struck out 20(!) batters but walked ten in the process.Walking a batter per inning against minor leaguers does not bode well for a future against major league hitters. However, Dunn only started pitching in 2006, so he has a fresh arm and the chance to harness his stuff.

If he can do that, he'll be a very dangerous left handed reliever.When news of the trade first broke, the word was that the Yankees had received Vazquez for Dunn, Melky, and a prospect. At that point, the trade seemed like an absolute steal for the Yankees. Then the news trickled in that the aforementioned prospect was Arodys Vizcaino .This stung a bit There is no doubt that Vizcaino was a top Yankees prospect. I ranked Dunn as the Yankees' 23rd best prospect and had Vizcaino ranked seventh.
I even admit I probably sold Arodys short a little bit at the time of my rankings.Recently, Baseball America ranked him the Yankees' fourth best prospect and best overall pitching prospect. Baseball Prospectus ranked him even higher, as the Yankees' number two prospect. Adding Vizcaino to the deal made it not such a steal anymore instead, it's an even trade. He had the highest ceiling of any pitching prospect in the system and could have even made the jump to Tampa to start the season.The scouting report on Vizcaino is a good one. After sitting at 91-94 for much of his time with Staten Island, he started building up arm strength. By the end of the season, he was sitting at 94-96 with good movement.