The Celtics have agreed to terms with James Posey, a player who should give the Celtics defense a significant upgrade.

This 6-8 forward, known in particular for his role as a defensive stopper on the 2006 Miami team that won the NBA title, averaged 7.7 points, five boards and one steal per game last season.

The deal came together with relative haste. Though Danny Ainge, the Celtics? director of basketball operations, had been in touch with Posey over the last month, discussions gained momentum yesterday, after Reggie Miller informed the Celtics that he would not come out of retirement to join the team.

By this afternoon, the sides had reached agreement on a deal that will pay Posey just over $3 million - the amount left on the team?s mid-level exception - next season. The full contract will pay him $7 million over the next two years, with Posey holding an option on the second season.