Boston Celtics legend Paul Pierce believes Kevin Garnett's No. 5 will soon hang alongside Pierce's No. 34 in the rafters at TD Garden. After Pierce's number was retired Sunday in Boston, the 10-time All-Star wondered if, in an era of players switching teams in free agency, it might be a while before Boston's next number retirement. Pierce later told ESPN that he believes Garnett is a slam-dunk to join him. "Without a doubt, KG's number will be [the next one] retired in Boston," said Pierce. "It's going to happen." Celtics president of basketball operations Danny Ainge said the team has had informal discussions about retiring Garnett's number, but that a final decision would come from ownership. Pierce, who played his first 15 seasons in Boston, signed a one-day contract with the Celtics last summer in order to retire as a member of the team. Celtics co-owner Wyc Grousbeck later called Pierce to tell him the team planned to retire his No. 34 this season. Pierce's was the 22nd number retired by the Celtics. Some argue that Garnett, who played six seasons in Boston after being acquired from the Minnesota Timberwolves, didn't have a long enough tenure to have his jersey retired. "It was six years of potential championship-caliber teams and All-Star play from KG," said Ainge. "I think that it was a pretty significant impact he had in those six years." Garnett is credited with changing the culture in Boston. The arrival of Garnett and Ray Allen helped the Celtics vault from a 24-win team at the bottom of the East in 2006-07 to a 66-win squad that brought home Boston's 17th title a year later.