Mookie Mania is officially upon us.
The No. 1 prospect for the Boston Red Sox, Mookie Betts, got his call to the big leagues Saturday and made his MLB debut against the Yankees on Sunday night. His ascension through the minors was an incredible success in player development, as Betts began the year without a single plate appearance above High-A.
Betts still has 127 at-bats to go before he loses eligibility on this list, but there's a new No. 2 prospect in the system nonetheless. With the season now more than half over, it's time to start rewarding minor leaguers who have performed this season and docking those who have struggled.
Players who have exceeded 130 PA or 50 innings pitched in the majors are not eligible for these rankings. All stats as of June 28, 2014.