It seemed not that long ago that the Yankees were blessed to have a surplus of young, exciting outfield prospects in their farm system. Slade Heathcott, Tyler Austin and Mason Williams all were either consensus Top 100 prospects or, if left off a particular expert's list, very close to it. In 2012 they all posted a wRC+ above 130 at their respective levels while Austin became the first to hit the AA level that year. It looked like in a year or two that the Yankees were going to have three major league ready outfielders with a lot of potential. Of course an embarrassment of riches in baseball tends not to last long as injuries and other pratfalls loom around every corner, and as such the Yankees now only have three young players with cratered value and very cloudy futures.
Heathcott is the one whose possible major league career is in the most jeopardy since he can't seem to stay on the field for any extended period of time. His knee continues to betray him as he only managed nine appearances this year at AA after having his 2013 cut short because of similar issues. It's hard to even assess what will become of Heathcott at this point since his athleticism was part of his upside and it may not be the same when he returns. For the time being his outlook is just a big question mark.
Tyler Austin has seemingly recovered from his own injury difficulties as his wrist issues appear to be behind him. Of course that's not the only matter of concern as Austin has yet to distinguish himself as a hitter at AA. As the least dynamic athlete of the three, Austin was always going to have to hit well in order to make it and that just has yet to happen (103 wRC+ in '13, 91 wRC+ in '14). The team has had him working at first and third to increase his versatility, but like the corner outfield spots he had been patrolling they're positions that are usually home to plus hitters. He's been hot as of late, so perhaps he's starting to turn a corner.
Mason Williams is the one I would wager still has the best chance of making an impact in the big leagues. He still has the speed and defensive tools that made him an exciting prospect, and even with his disappointing 60 wRC+ this year there are positive signs. His walk rate is up and his strikeout rate is down, while his BABIP is almost 50 points lower than last year but slowly normalizing. It seems he's gradually recovering from an absolutely hideous start to his season. His ceiling may never be more than as a serviceable hitter, but he could still make it on the strength of his other talents.
While it's unfortunate that these three youngsters have all but evaporated their trade value, they still have plenty of time to possibly contribute for the Yankees. None of them are yet what you would consider "old": Heathcott will be the senior of them at 24 next season. Not every player can make a continual, swift ascent up the minor league ladder. As Dellin Betances has shown, sometimes the process is a long and drawn out one. You just would have hoped that one of the three would have been knocking on the door of the majors by now.