Chiefs running back Jamaal Charles is going back on injured reserve after developing swelling in his surgically repaired right knee, a person familiar with the decision told The Associated Press. Another source said he will need another surgery. The Chiefs have not announced the move. The designation means the Pro Bowl back will miss at least eight weeks. Charles had only 12 carries for 40 yards in three games this season.

n WR Harvin rejoins Bills

Using the past six months to rest his mind and rehab numerous injuries that led him to walk away from football in April, Percy Harvin was back on the practice field yesterday shortly after signing a one-year contract with Buffalo.

“It felt good, just the smell of the grass again, the smell of the pads when I walked in the locker room,” Harvin said.

“Man, when you’re away from it, you miss so much of those things.”

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Harvin returns to the team he essentially walked out on a year ago, when he did not travel overseas for Buffalo’s game in London. He blamed that decision on being in constant pain from a knee injury that was also affecting his hip.

Limited to just five games last season, Harvin, 28, had 19 catches for 218 yards and a touchdown before being placed on season-ending injured reserve.

n Eagles’ Huff charged

Philadelphia Eagles wide receiver Josh Huff was charged with possession of a 9 mm handgun without a permit and having a small amount of marijuana after he was pulled over in Camden County, New Jersey, for speeding, according to a court complaint. Huff was pulled over on the New Jersey side of the Walt Whitman Bridge around 11 a.m. yesterday. New Jersey has very strict gun laws.

n Williams suspended

Washington left tackle Trent Williams has been suspended four games for violating the NFL’s substance abuse policy. It’s his second four-game suspension, after testing positive multiple times for marijuana during the 2011 season . . . Detroit defensive end Armonty Bryant has been suspended three games for violating the substance abuse policy. Last month, Bryant was cut by Cleveland at the end of a four-game suspension.— AP