Joe Thomas: Johnny Manziel must win back Browns' trust

Cleveland Browns quarterback Johnny Manziel, who is undergoing voluntary rehab treatment, will have to prove to his teammates that he's dedicated to winning, offensive tackle Joe Thomas said Monday.

"I think he's going to have to prove to the team that football is important and being 'the man,' being the starting quarterback for the Cleveland Browns, is important, it is his goal, his single goal in his life," Thomas told ESPNCleveland.com.

"You know, I think he lost probably a lot of trust among the guys on the team last year by the way he handled himself once he became the starter. And I think he had a lot of time to reflect, I'm guessing, after the season was over by the comments he made in the media and by his actions, checking himself into rehab. ... I think those were really positive steps."

Manziel voluntarily entered treatment Jan. 28 as a direct result of his lifestyle away from the field, and he informed people in his circle before entering treatment that he wants to "figure out his value system," a source told ESPN.com.

He's expected to attend the Browns' offseason workouts, which begin April 20. Manziel, who took an Easter weekend trip with his family, is allowed to make occasional trips as part of his rehab program.

"I'm hoping when we come back in April, we see a new Johnny and everybody's blown away with his commitment," Thomas told ESPNCleveland.com. "And I think he's got the talent, so it's just a matter of if he commits himself to it, we can have a really good quarterback on our hands."

However, Thomas, an eight-time Pro Bowl tackle, said the Browns have taken the right steps this offseason by signing free-agent QB Josh McCown.

"Obviously there's some uncertainty with Johnny right now and that's why we brought in Josh," Thomas said. "He's a guy that if he's asked to carry the flag this year, he's going to do a great job. There's a chance we draft somebody or there's a chance Johnny comes back and he's a new person and he's rededicated to football, and he turns into the great quarterback that we expected when we drafted him in the first round."

Manziel, selected by the Browns with the 22nd overall pick in the 2014 draft, completed 18 of 35 passes for 175 yards in seven quarters of NFL play before injuring his hamstring in Week 16.