The Boston Red Sox figure to be among the most active teams in both the free-agent and trade markets this offseason.

They need to fill at least two spots in their starting rotation. They need to solidify third base. They need to bolster their bullpen, and they could decide they need a new backup catcher, too.

That means that in addition to spending money, the Red Sox are likely to make some trades. With logjams in the outfield, at first base and in the Triple-A rotation, the Sox are well poised to make a splash or two in the coming months.

And while players such as Xander Bogaerts, Mookie Betts, Christian Vazquez, Allen Webster, Brandon Workman and Jackie Bradley Jr. all lost their rookie eligibility last season, there’s still plenty of talent in the Sox’s system that can be used to acquire prominent major leaguers.

That being said, let’s take a look at the five prospects Boston should try the hardest to hang on to this offseason. Any of these players are movable in a megadeal—a package for Giancarlo Stanton or Chris Sale, for example—but the Red Sox should be judicious in their willingness to include them in lesser packages.

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