The team said Green will undergo surgery Jan. 9 at the Cleveland Clinic.
The club said Green should be able to resume his career next season, and that if his contract is voided, as expected, the Celtics would have first rights to re-sign him as a restricted free agent.
Green, who could not be reached for comment, did address his situation on Twitter shortly after the announcement.
“Thank you everyone for your thoughts and prayers… much appreciated love you all… and I’ll be back soon stronger and better than ever I promise,’’ he tweeted.
According to the Mayo Clinic website, an aortic aneurysm is an “abnormal bulge that occurs in the wall of the major blood vessel [aorta] that carries blood from your heart to your vital organs.’’
Per Green’s wishes, Ainge and coach Doc Rivers did not speak about his condition, but Ainge did release a statement.
“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,’’ he said. “The entire Celtics family supports Jeff during this difficult time in his career.’’
Rivers hinted after Friday night’s scrimmage at TD Garden that Green would miss extensive time. “I’ll let you guess,’’ was his answer when asked whether he planned to prepare for Green’s long-term absence.
Green was acquired by the Celtics Feb. 23 in a controversial trade that sent Kendrick Perkins to the Thunder. Green’s play was uneven last season, as he averaged 9.8 points and 3.3 rebounds in 26 games.
Green put up shots before practice Tuesday and Wednesday but was not cleared for full contact. On Thursday, when the team worked out at the Garden, Green said he did not want to speak with the media.
According to Dr. Nancy McNamara, an interventional cardiologist at Bakersfield (Calif.) Heart Hospital, Green should be able to resume his career.
There are three types of aortic aneurysms, and it is uncertain which type Green was diagnosed with.
