Rubby De La Rosa, RHP, Pawtucket Red Sox (Triple-A)
Though no longer technically a prospect, "RDLR" could still be an important part of the 2014 big league club. He's allowed just one earned run though 10.2 innings and two starts so far this season, striking out nine and walking just two. De La Rosa's ultimate future may be in the bullpen, but his performance has been nice to see, nonetheless.
Brian Johnson, LHP, Salem Red Sox (High-A)
Johnson has had a very rough start to the 2014 season, giving up 11 earned runs in 13.2 innings. A college product from Florida, Johnson is hardly young for his league and should be producing better results given the competition. If there's one bright spot, it's that he already has 20 strikeouts.
Manuel Margot, OF, Greenville Drive (Single-A)
The man many picked as Boston's biggest breakout prospect candidate this season, Margot has acclimated nicely to Single-A, posting a .290/.333/.613 line in 33 at-bats so far. A plus-plus defensive prospect, Margot could enter the national prospect discussion with a step forward offensively.
Deven Marrero, SS, Portland Sea Dogs (Double-A)
Boston's first-round pick in the 2012 draft, Marrero has begun the year hitting quite well in Double-A, putting up a .355/.394/.516 line in seven games and 31 at-bats. Marrero's defense might be MLB-ready now, and his offense will determine whether he serves as a down-the-order starter or a good utility infielder in the majors.
Wendell Rijo, 2B, Greenville Drive (Single-A)
Another sleeper prospect in the Red Sox system, Rijo is hitting .321/.441/.500 through 28 at-bats. The athletic middle infielder has already hit two doubles and a homer, and he could be in line for a midseason promotion with a strong performance this year.