OAKLAND (CBS SF) — Suspended Oakland Raiders defensive end Aldon Smith has entered a treatment center days after a video emerged on social media hinting at possible marijuana use.

Quoting several unnamed sources, TMZ Sports reported Friday that the troubled Raiders star has checked into an unnamed rehab clinic. It would be his second stint in a rehab center.

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Smith also entered rehab as a member of the San Francisco 49ers after a DUI arrest, other legal woes and a league suspension.

Meanwhile, the National Football League is reportedly investigating Smith after a Periscope video was posted showing a man allegedly claiming to be Smith smoking what appears to be a marijuana cigarette.

The league is investigating whether Smith violated the league’s substance abuse policy, NFL.com reported Monday. Smith has been serving a one-year suspension since November for violating the policy.

The video, titled “Fire up Session” (note: explicit language) was posted on a Periscope account that features Smith in many of its videos. In the video, a man is seen holding what appears to be a blunt – a hollowed-out cigar filled with marijuana – and talking with a female companion.

The man’s face is not seen, but at the end of the video he’s saying “[T]hey don’t know it’s me. It’s not like I put ‘Aldon Smith.’”

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In a tweet posted Monday, Smith denied the allegations.

Smith, who joined the Raiders for the 2015 season, previously played for the 49ers and had numerous troubles on and off the field.

San Francisco released Smith last year after he was arrested in Santa Clara on charges of drunken driving, hit and run and vandalism. Smith has pleaded not guilty.

During the 2014 season, Smith served a nine-game suspension for violating policies on substance abuse and personal conduct. Smith was also arrested that year for being uncooperative during a security screening at Los Angeles International Airport. No charges were filed.

Smith has also pleaded no contest to a 2013 drunk driving incident in San Jose and possession of assault weapons.

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