Tim Duncan will sign a three-year contract with the Spurs this week, league sources told Yahoo! Sports.

Duncan's representatives and the Spurs are finalizing a few items in the contract, but the structure has been agreed upon. The contract has a player option for the third season and is fully guaranteed. The deal also has a no-trade clause, sources said, and should take Duncan to the end of his playing days.

The Spurs have reached agreements with free agents Danny Green (three years, $12 million) and Boris Diaw (two years, $9.2 million). They also have struck a deal to re-sign guard Patty Mills, who opted out of his contract after last season, and intend to add French guard Nando De Colo.

Duncan, 36, declared himself "a Spur for life" during the Western Conference finals, and showed little interest in testing the free-agent market. He averaged 15.4 points and nine rebounds last season.