Cleveland Browns quarterback Johnny Manziel entered a treatment facility last Wednesday, according to a family adviser.

A statement from his adviser, Brad Beckworth, did not say why Manziel is in treatment.

"Johnny knows there are areas in which he needs to improve in order to be a better family member, friend and teammate and he thought the off-season was the right time to take this step. On behalf of Johnny and his family, we’re asking for privacy until he rejoins the team in Cleveland," Beckworth said.

Recently, some of Manziel’s teammates were quoted in an ESPN story questioning Manziel’s work ethic and his off-field behavior. He was fined for not showing up for the team’s final walkthrough last season, with one player saying that Manziel thought his rookie season was a "100 percent joke."

According to ESPN.com's Darrell Rovell, Manziel was offered six figures by a Las Vegas casino to host a Super Bowl party this weekend but turned it down.

Browns general manager Ray Farmer released a statement on the team's website on Monday:

"We respect Johnny's initiative in this decision and will fully support him throughout this process. Our players' health and well-being will always be of the utmost importance to the Cleveland Browns. We continually strive to create a supportive environment and provide the appropriate resources, with our foremost focus being on the individual and not just the football player. Johnny's privacy will be respected by us during this very important period and we hope that others will do the same."

On Dec. 29, after the Browns' season was over, Manziel said he wanted to take responsibility for his behavior. "It's about actions, it's about being accountable instead of looking like a jackass," he said

The 22-year-old's off-field behavior has drawn attention since he was a Heisman-Trophy winning quarterback at Texas A&M.

The Browns selected Manziel with the 22nd pick in the first round of the 2014 NFL draft. In five total games, including two starts, he completed 18 of 35 passes for 175 yards with no touchdowns, two interceptions and 29 rushing yards before missing the season finale with a hamstring injury.

- Scooby Axson