Apr 16, 2009 2:40 PM EST

"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.

Via Boston Globe