The ​Red Sox are feeling good coming off of their fourth World Series win since 2004, but they may not be able to keep some of their key players for much longer. 

According to reports, it's expected t​hat ​J.D. Martinez and ​Xander Bogaerts, who will be free agents next year, are likely to test free agency. The pair haven't ruled out signing long-term deals with the Red Sox, but the two are believed to be interested in testing free agency before committing to Boston.

A big issue is that the two are represented by mega agent Scott Boras.

​​Martinez's contract features multiple opt-outs, which begin next season, so he would be able to opt-out of his deal and sign a bigger contract. Martinez didn't receive as much interest in last year's free agency as expected, so perhaps he feels he can earn a larger deal by testing the market.

Bogaerts, on the other hand, plays one of the most sought after positions in baseball and Boras will demand nothing less than superstar money for the 26-year-old. 

Martinez and Bogaerts both had outstanding seasons in 2018. Martinez slashed .330/.402/.629 with 43 home runs and a league-high 130 RBI. Bogaerts hit a career high 23 home runs while hitting .280/.360/.522. These guys are on the fast track for big bucks.