Bill Strickland, Wallace's agent, told the Boston Herald and the Boston Globe on Sunday night that the 34-year-old forward told him to call off meetings the agent was in the process of scheduling with the Orlando Magic, San Antonio Spurs and Dallas Mavericks.
The Boston Globe reported Wallace will sign for two years at the midlevel exception.
Wallace won a championship with the Detroit Pistons in 2004 after arriving in a midseason trade, although his career has been noted just as much for his volatile interactions with officials and contentious relationships with coaches. However, the strong presence of veterans such as Kevin Garnett, Paul Pierce and Ray Allen in the Celtics' locker room should keep Wallace in line and bring the focus to his positive attributes: The 6-foot-11 Wallace is a scoring threat from the low block to the 3-point arc and a long-armed, savvy defender.
"As much as Rasheed's a headache, teammates like him and he's a winner," an NBA executive said.
After trade rumors involving Allen and Rajon Rondo surfaced last month, it appeared the Celtics might be trying to shift on the fly, at the risk of breaking up the core that won the 2008 NBA championship. Now the Celtics have landed a piece that makes them a prime contender to win again next season, with an emphasis on the short term. Wallace will be 35 in September and made joining a championship-caliber team a priority this offseason.
But Boston was always the leading contender, a positioned strengthened by a dinner meeting with Wallace involving Garnett, Pierce, Allen, coach Doc Rivers and owner Wyc Grousbeck last week.
Wallace restores frontcourt depth to the Celtics, who did not extend a qualifying offer to Leon Powe and could lose restricted free agent Glen Davis if another team signs him to a contract the Celtics decide not to match.
J.A. Adande is a columnist for ESPN.com. Information from The Associated Press was used in this report.