Oakland Raiders WR Antonio Brown cleared to practice after trip to NFI list

July 28 (UPI) -- Oakland Raiders star wide receiver Antonio Brown was cleared to practice Sunday after a short stint on the non-football injury list.

League sources told ESPN and the NFL Network that Brown passed his physical and returned to the field two days after he was put on the NFI list. He was added to the injury report Friday, but no details were provided as to why Brown was placed on the non-football injury list.

Brown caught passes on the practice field Sunday, but the team remained cautious and eased the star wideout back in to training camp. After taking part in pre-practice drills, he didn't participate in stretch or group drills, according to ESPN.

The Pittsburgh Steelers traded Brown to the Raiders this off-season after nine seasons with the franchise. He recorded 104 receptions for 1,297 yards and 15 touchdowns in his final season with the Steelers.

Brown made his first appearance at Raiders training camp by arriving in a hot air balloon Friday in Napa, Calif.

The Raiders open the preseason against the Los Angeles Rams on Aug. 10. Oakland plays the division rival Denver Broncos on Sept. 9 to begin the regular season.