#8. Mike Moustakas, Kansas City Royals
2015 WAR: 4.4
2014 WAR: 0.4
WAR Improvement: 4.0
When a player finally learns how to hit to the opposite field, amazing things can happen.
During his rookie season with the Kansas City Royals, Mike Moustakas put 22.7 percent of his batted balls into the relevant area, and that mark remained the highest of his career through 2014. But in 2015, his opposite field percentage jumped to 27.4, forcing opponents to stop throwing so many shifts at him and opening up more feasible green space.
Throw in some of the power he flashed during his minor-league career — remember, the third baseman blasted 36 homers in 2010 between Double-A and Triple-A — and you can easily see what was behind Moustakas’ spike in value.
He’s still going to pop out to infielders a bit too often, and plenty of his contact will result in lazy fly balls to shallow territory. But the changes are all positive and fall in line with what once made this 27-year-old such an intriguing prospect.
Now that he’s actually broken out and proved himself a late bloomer, there’s no reason to expect any significant backsliding.