MLB roster expansions are nearly upon us, and the Boston Red Sox certainly have no shortage of intriguing players they can call up once the calendar turns to September 1.

This is already a team loaded with young talent, to be sure.

Xander Bogaerts, Mookie Betts and Christian Vazquez play nearly every day, while Rubby De La Rosa, Brandon Workman, Anthony Ranaudo and Allen Webster are vying for starts. The bullpen has seen an infusion of youth from the likes of Heath Hembree and Tommy Layne, and relatively young players like Brock Holt and Will Middlebrooks are seeing plenty of time as well.

Yet, Boston could get significantly younger in the coming days, as the likes of many of its remaining top prospects could see their first taste of MLB action when rosters expand. Unfortunately, the Sox have so many deserving or intriguing candidates that some players will inevitably be left out.

To that end, let’s look at Boston’s five best prospects in the upper minors who are least likely to get a call to the majors in September, and who will have to wait for 2015 or beyond for the call instead.

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