The 30-year-old shortstop from Aruba will be a free agent. He has been a Red Sox player since 2013. Bogaerts played in the minor leagues and the Dominican Summer League after the team signed him in 2009 before promoting him to the major leagues. In addition to his value at the plate, Bogaerts is a top defender at his position and was a nominee for the Gold Glove award the previous season.
Bogaerts has expressed his optimism that this season won't be his last with Boston. At the team's end-of-year press conference, Chief Baseball Officer Chaim Bloom stated that re-signing Bogaerts is still a top priority.

"The Redsox have "sweetened" their offers to Xander Bogaerts and Rafael Devers since Free Agency has begun. Something to keep an eye on" - BostonEmpire247
How does Boston Red Sox assess the curent situation with Xander and some other big names?
According to team president Sam Kennedy, the Red Sox have extended two new contract offers to Xander Bogaerts and one new contract offer to Rafael Devers since the conclusion of the season. The offer's conditions have not been disclosed. Devers will become a free agent next offseason, while Bogaerts is already a free agent after choosing to forego the last year of his deal.
"Sam Kennedy on NESN: Xander and probably all the fans are tired of hearing us profess our love for him. ... It's our hope to keep him around here a long time. We're going to do our very best." - alexspeier
Boston "should have engaged more successfully" with Mookie Betts earlier in his career, according to Kennedy. During his stint with the Red Sox, Betts turned down many below-market extension offers before being moved to the Dodgers a year before the start of his free agency. Despite this, Boston allowed things to progress to the point where Bogaerts chose to forego his contract, and Devers will soon be a free agent.
Is there a major roster change in the store for the Red Sox?
The deadline for teams to submit contracts to arbitration-eligible players is tomorrow, Nov. 18th. Hence, a slew of new free agents will enter the market. (Some have already been designated for assignment and linked to Boston, such as left-handed pitcher Ryan Yarbrough of the Tampa Bay Rays.)
After that, the Red Sox's rebuilding process should start, and the dominoes should start falling. With or without Devers and Xander Bogaerts.