Matsui was advised Monday by specialist Dr. Scott Rodeo, who performed the surgery on Matsui's right knee last November, to have season-ending surgery on a left knee that's caused recurring inflammation since June 18. Matsui was placed on the disabled list June 27.
Matsui said the knee feels better than when he went on the DL. It has less fluid and swelling, and fluid was removed about a week ago.
"If I were to get surgery right now, I wouldn't be able to come back this season," Matsui said through a translator, adding, "I still have a strong desire to want to come back this year and be a force for the team. In that sense, to me that was more important, so that's why I'm taking this approach."
Matsui started 22 games in the outfield and 43 games as a designated hitter, a role he'd come back to if he returns.
"Hideki I have not been optimistic on," general manager Brian Cashman said. "We've been treating him conservatively, but I have not been optimistic that that would work, just because of how he's responded throughout the process."
Willie Bans is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.