Seattle ? Free agent guard Brent Barry has reached agreement to join the San Antonio Spurs, leaving the Seattle SuperSonics to play alongside Tim Duncan and improve his shot at an NBA title.

“Brent called and informed us that if everything goes according to plan, he expects to sign with San Antonio,” Sonics general manager Rick Sund said Saturday. “If that’s the case, we certainly wish him well.”

The four-year deal is believed to be worth between $22 and $24 million.

Seattle initially offered the 32-year-old Barry three years at $17.75 million, with a counteroffer near San Antonio’s proposal but worth more in the first three years and with a partially guaranteed fourth year.

Instead, Barry chose to join one of the NBA’s elite teams. He’s also likely to extend his career as a spot shooter coming off the bench.

Sund refused to confirm details of either team’s proposal. Teams cannot discuss agreements until Wednesday, when free agents can begin signing with teams and the salary cap is set for next season.