"Yes, he's out," Doc Rivers told the Boston Globe about Kevin Garnett's status.  "I feel for the season, but we just don't know yet."

Rivers initially made the surprise announcement during a radio interview earlier on Thursday.

The injury keeping Garnett on the sidelines is a strained popliteus tendon, not the bone spur which Rivers said will likely require off-season surgery.  

Garnett's knee is only 70 percent healed.