Garnett, who turned 38 in May, is due $12 million in 2014-15, which would be his 20th NBA season.
He has yet to publicly announce that he's playing this season, but all indications continue to point that way. On Saturday, a league source told ESPNNewYork.com that the Nets still expect Garnett to return.
Pierce elected to sign a two-year contract with the Washington Wizards for $11 million with a second-year player option, sources told ESPN.com.
Pierce and Garnett had been teammates since 2007-08. They won a championship together with the Boston Celtics.