As a 24-year-old, Vaughn hit .267/.346/.424 in 71 games in AA. An elbow strain kept him out of the AA lineup from June 2 through August 6.
I no longer view Vaughn as a potential everyday contributor for the Mets. The move to AA really exposed him. His strikeout rate of 26.5% in AA this year was his highest at any minor league stop, while his walk rate of 8.2% was his lowest. His .156 isolated slugging percentage was his lowest since Savannah and his 6.8% extra-base hit rate exceeded only Savannah (6.7%), and even at that by only one tenth of a percentage point. For reference, the Eastern League had an extra-base hit rate of 7.2%, a strikeout rate of 20.1% and a walk rate of 9%. So, Vaughn hit for below average power, walked at a below average rate and struck out way above AA average. His season line looks better thanks to a .345 batting average on balls in play, his best rate since Savannah, and one he seems unlikely to replicate with consistency against upper level competition.
Again, in 2013, Vaughn displayed extreme platoon splits that have been present in his performance in the last three years. In 2013, he hit .242/.327/.374 in 198 AB against righties and .344/.403/.578 in 64 AB against lefties. In the last three years, through the full-season minor league levels, he has bashed .296/.401/.528 in 409 PA against lefties and .231/.335/.383 in 1047 PA against righties. At this point, it seems extremely unlikely that Vaughn will magically figure out how to hit righties.
Can a Major League team afford to roster a corner outfielder who only hits lefties and does not play centerfield? Sure, straight platoons are possible, still, right? Oakland?