Yoan Moncada is the best prospect in the Red Sox organization. There isn't much of a debate to be had on the matter -- Andrew Benintendi is promising, but he's older and less established, and neither of Rafael Devers or Anderson Espinoza are proven enough to unseat Moncada and his five-tool skill set.
Given all that, it's not a huge surprise to hear that Moncada is also the top prospect at his position in the minors, with MLB ranking him number one among second base prospects.
Moncada began his 2015 a little slowly, first playing in extended spring training then moving on to Low-A Greenville. Just 20 years old and away from the game for a year, Moncada took a little time to adjust to pro ball stateside, but once he did adjust, he was nigh unstoppable. Moncada hit .200/.287/.289 over his first 25 games and 101 plate appearances, then .310/.415/.500 over his final 56 and 262. He went 45 for 48 in stolen bases in that stretch, and while he struck out 21 percent of the time, he made plenty of quality contact in between.
There's still work for Moncada to do, obviously, but he should end up splitting 2016 between High-A and Double-A. The Sox might even get a little aggressive and send him straight to Double-A Portland, as his Low-A experience had more to do with letting him acclimate to his new environment and getting back into a routine than with his abilities.
Jonathan Mayo covered second base for MLB, and had basically nothing but good things to say about Moncada in his scouting report:
Few middle infielders can match Moncada's huge offensive ceiling, which earns him comparisons to Robinson Cano with more speed. He's a switch-hitter with outstanding bat speed who makes consistent hard contact from both sides of the plate. Moncada doesn't have much loft in his swing, which could cap his home run production at 15 annually, though he has the potential for 20-25 per season if he alters his approach.
Moncada's best pure tool is his well-above-average speed, which he put to good use by stealing 49 bases in 52 attempts last season. His quickness doesn't translate consistently as well in the field, where he looks tentative at times at second base. But Moncada should be at least an average defender at second base, and he has the range and arm strength to play almost anywhere on the diamond he might be needed.
As stated, his defense probably needs a little work, but he's still just going to be 21 this year, and he might not stick at second, anyway. With Dustin Pedroia around, Moncada doesn't necessarily have to stay at the keystone -- while third base is also full, who knows what goes down in the outfield over the next couple of years, and Pablo Sandoval might have a tenuous grip on the hot corner, anyway.
Either way, where he plays isn't that important a question right now, because his bat and athleticism will let him work out just about anywhere. When he's on the cusp of the majors, the Red Sox will need an answer to the where, but for now, letting him focus on his bat should do just fine. Remember, Mookie Betts didn't become an outfielder until halfway through 2014 -- these aren't things that always need to be known about a prospect as early as possible.
Moncada is the third Red Sox prospect to make one of these positional lists so far, with Sam Travis ranking in the top-10 at first base and Anderson Espinoza making it to the top-10 for right-handed pitchers. MLB has yet to unveil third base, shortstop, and the outfield, but the Sox should see at least a couple more representatives from those groups before these lists are done.