(Reuters) - New England Patriots quarterback Tom Brady missed a second straight practice on Thursday due to a knee injury, the BostonHerald reported, putting his availability for Sunday's game in doubt.

The origin of Brady's injury is unclear as he played the full game in Patriots' 30-17 win against the San Francisco 49ers on Sunday.

The Patriots are set to play New York Jets on Sunday and the 39-year-old Brady would likely need to practice on Friday before playing in that contest. According to the Boston Herald, it has been at least eight years since a Patriots player has missed all three practices and played in a Sunday game.

Brady has been on a torrid pace since returning from his four-game suspension at the start the season.

The Patriots are tied for the top spot in AFC at 8-2.

(Writing by Jahmal Corner in Los Angeles; editing by Sudipto Ganguly)