The Celtics said Saturday that surgery "should completely repair" the condition, though Green will miss the 2011-12 season. He is expected to be able to resume playing next season.
"While we are saddened that Jeff will not be able to play this season, the most important thing is his health, and we were fortunate to have access to an amazing team of specialists to evaluate Jeff's case," said Celtics president Danny Ainge. "The entire Celtics family supports Jeff during this difficult time in his career."
The aneurysm -- which occurs when a section of the aorta weakens and expands, putting it at risk of rupturing -- was detected during a December 9 physical. Doctors recommended surgery after Green underwent additional tests. He will have surgery at the Cleveland Clinic.
Boston acquired Green from Oklahoma City last February in the trade that send Kendrick Perkins to the Thunder. He averaged 9.8 points and 3.3 rebounds in 26 games for the Celtics, and has career averages of 13.9 points and 5.5 rebounds in four seasons.