BOSTON — The Boston Red Sox didn’t just build a World Series champion in 2013.

They also created a blueprint for the team’s next title.

The Red Sox took advantage of last August’s salary purge to add middle-market free agents like Mike Napoli, Jonny Gomes, Shane Victorino and Koji Uehara — all key contributors to the World Series championship. As he looks to this offseason, general manager Ben Cherington will need to replace some big parts of the ’13 team — including center fielder Jacoby Ellsbury — without making the free-agent mistakes of the past.

“To be in this position, given where we’ve come from, reflecting back a year ago at this time, there’s been a lot that’s happened in 13 months,” manager John Farrell said after the game. “Ben Cherington deserves all the credit in the world for what he has done for this roster.”

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The Red Sox were still smarting from their 2011 collapse when they traded Josh Beckett, Carl Crawford, Adrian Gonzalez and more than $250 million in future salaries to the Los Angeles Dodgers last August. Although the team finished in last place, with the franchise’s worst record in almost half a century, the rebuilding had already begun.

Instead of showering money on the biggest names to replace the high-priced talent that had departed, Cherington opted to take smaller risks on midrange players.

It paid off with Uehara, Victorino, Napoli and Gomes all delivering in big ways throughout the postseason.

But now it’s time for the sequel.

Ellsbury is a free agent, and agent Scott Boras is expected to demand a nine-figure contract. Napoli is also unsigned for next year, along with shortstop Stephen Drew and catcher Jarrod Saltalamacchia. The team will almost certainly prevent pitcher Jon Lester from becoming a free agent by picking up his $13 million option.

Farrell doesn’t know how the team will replace those who leave.

But he is hoping the improved clubhouse atmosphere will help the team sign any free agents they target.

“I think maybe what’s gone on around the game or what’s happened here probably is taken note around the league,” Farrell said before the clinching 6-1 victory over the St. Louis Cardinals in Game 6.