SS, Angel Aguilar: Probably more so than any of the other names in this group, this Venezuelan native battled nagging injuries all season long that aided in his rather disappointing showing in 2015. His star was on the rise entering the 2015 campaign after hitting .311 with seven home runs in the Gulf Coast League in 2014 but he was set back pretty much from the start of the year after dealing with a back injury in Spring Training. In fact, his health issues were the main reason he began the year in Extended Spring Training and didn't make his long-season league debut until late April with the Charleston RiverDogs.
He also saw extended playing time at other positions too, playing a lot of second base and third base for the first time in his career and that kind of utility role does take some time to adjust to. Still, he amassed 345 at-bats for Charleston this season, the third highest total on the team, and he finished his year hitting just .229 and saw both his walk ratio drop and his strikeout rate increase from seasons prior. With the overall depth of quality middle infield prospects down on the farm for the Yankees it will never be a good time for a disappointing showing for whatever reason and there's no mixing words, Aguilar's season was disappointing for sure.
OF, Tyler Austin: Nobody arguably had a more disappointing season down on the farm for the Yankees than this former Yankees Minor League Player of the Year. A career .336 hitter entering the 2013 campaign, this Georgia native battled wrist issues for the better part of two seasons and saw his numbers drop rather dramatically as a result. He seemed to turn a corner health-wise, however, in the second half last season, hitting .336 after the All Star break and was once again one of the real standouts in Spring Training this year too but then proceeded to hit a career-low .240 in two minor league stops in 2015.
Not only was his .240 a career low but so were his 13 doubles; to put that into perspective, Austin hit 18 doubles in nearly half the games played back in 2011 in the short-season leagues. His rather disappointing showing this year not only had him demoted from Triple-A to Double-A late in the season but it also had him removed from the 40-man roster too. Unlike most of the other names in this group who still have considerable time to turn things around, Austin needs a bounce-back season immediately in the worst way.
3B, Dante Bichette Jr.: It's a coin flip between Austin and this former first round pick for who had the most disappointing season at the higher minor league levels for the Yankees in 2015. The numbers suggest it is Bichette though after he hit just .226 with three home runs in 112 combined games between Double-A Trenton and high-A Tampa. Like Austin, Bichette's disappointing season included a late-season demotion and now he finds himself buried on the positional depth chart for the Yankees.
He seemed to have turned a corner in 2014 too, hitting .271 with a .763 OPS for the high-A Tampa Yankees after hitting just a combined .232 over the two seasons prior at the low-A level, but his lackluster 2015 performance now suggests his 2014 showing was most likely the outlier. Considering his biggest attribute on the field is his bat more so than his defensive play, that's not a good sign for the now 23-year old. Like Austin, he is extremely short on time to prove his worth in the Yankee organization.
OF, Juan De Leon: There was a ton of excitement when the Yankees were able to land this high-profile International free agent out of the Dominican Republic last year for a reported $2 million and for good reasons; he had top-shelf tools, including above average speed and power, and most notably his advanced hitting approach. However, while it's tough to criticize any first-year player in his debut season, a season that includes a ton of learning, the fact is this 'hitter-ish' outfielder batted just .226 in the Dominican Summer League and by all accounts really struggled to make any real adjustments at the plate, and that is disappointing for somebody whose game profiled as more polished than that when he first signed.
The good news is he just turned 18 years old last month and still has plenty of time on his side to turn things around, especially now that he was served an ample dose of humle pie in his debut season. Still, while it would be a fool's errand to even begin thinking of writing him off as a viable long-term option for the Yankees, his debut was clearly one of the more disappointing ones not only among the high-priced International class last season for the Yankees but in the farm system in general.
OF, Alexander Palma: Though he just completed his third professional season in 2015, there are some apt comparisons between De Leon and Palma, most notably an advanced feel for hitting. Palma, signed back 2012, had proven that advanced bat too in his first two seasons, hitting .287 in his debut season in the Dominican Summer League before hitting a robust .305 with just 15 strikeouts in his first taste of the United States in 2014 with the Gulf Coast League Yankees. He wound up batting just .202, however, in low-A Charleston this past season and had just nine extra-base hits in 81 games.
The lack of power is pretty much expected though from a 19-year old in his first taste of the long-season leagues, especially considering he was batting under the lights for the first time in his career and also hitting in a pronounced pitcher's park. It is the rather inconsistent bat though that is more problematic as consistency had been his trademark signature calling card as a player entering the season. In fact, noted more for his bat than any of his other rather average tools, to label his lackluster performance [one that included just one four-game hit streak all season long] "disappointing" would be an understatement.