In announcing the suspension, the league did not say what banned substance Hargrove tested positive for. Under league rules, players face a minimum four-game suspension for the first positive test, followed by an eight-game suspension for second-time violators.

Bills spokesman Scott Berchtold declined comment citing a confidentiality clause that's included in the substance abuse policy. Hargrove's agent Philip Williams, did not immediately return a message.

The Bills were off today, a day after a 13-10 win at New Orleans. They return to practice tomorrow at their training camp facility in suburban Rochester.

The suspension is the latest problem for Hargrove after the third-year NFL player was arrested and charged with three misdemeanors stemming from a confrontation with police outside a Rochester nightclub last weekend.

Hargrove pleaded not guilty to the charges and also apologized to fans and his teammates, saying: "I need to hold myself up better than this. ... It's time for me to be a man and take responsibility in myself."

He is next scheduled to appear in Rochester city court on Aug. 21.

Hargrove's suspension begins Sept. 1, and he'll be eligible to return to the Bills' active roster on Oct. 1, a day after the team's game against the New York Jets. He will, however, be allowed to practice with the team and play in the Bills three remaining preseason games.

Hargrove is entering his second season with Buffalo after the Bills acquired him in a trade with St. Louis in October. He appeared in 10 games with Buffalo last season and was expected to continue his role this year as one of the team's two primary backups.

His suspension leaves the team with three experienced ends, starters Aaron Schobel and Chris Kelsay, and backup Ryan Denney.

A restricted free agent this offseason, Hargrove was re-signed by the Bills to a one-year, $850,000 contract.