Sometimes prospects don't work out. It could be because they're young, they get hurt, they don't make adjustments, or they just weren't as good as everyone thought to begin with. Here are a handful of prospects from my preseason top 100 who took a step backward in 2016. (Preseason rankings were from February.)

Brad Zimmer, OF
Cleveland Indians
Preseason rank: No. 21

Zimmer had no trouble with the low minors through 2015, but Double-A and Triple-A pitching exposed some real weaknesses in his game. Many left-handed-hitting prospects struggle to hit left-handed pitching, but Zimmer has been exceptionally poor in that area and isn't really improving. He struck out in one-third of his plate appearances against southpaws and hit .179/.343/.250 against them. His contact rates against right-handers aren't great either (29.5 percent strikeout rate this year), but he produces when he does make contact against them. Zimmer's swing can get long, and he tends to expand the zone too much when he's behind in the count, which happens often because he's patient and typically sees a lot of pitches. His power/speed upside is still here, but he needs a quantum leap in his approach for 2017.