Nine-time Pro Bowl left tackle Walter Jones will have his second knee operation in eight months, leaving his playing status in doubt.

Seattle Seahawks coach Jim Mora said after practice Wednesday that Jones will have arthroscopic surgery on his left knee Thursday morning.

Jones had microfracture surgery in December. He has missed all but three days of practice in training camp.

The 35-year-old anchor of Seattle's offensive line for the last decade tried to practice Monday but left midway through the session.

Mora said there could be "loose bodies" inside the knee. He said the procedure is just "to check it out." He is optimistic Jones will return this season.