"I think the only thing that was apparent probably was that there were other things in his life that were maybe getting in the way of committing himself the way an NFL quarterback needs to," Thomas said at the Cleveland Convention Center after the team unveiled its new uniforms.
Thomas did not specify what those things were, nor did he say he knew. He just said the commitment from an NFL quarterback has to be higher than at any other position.
"It's a different level completely," Thomas said.
Manziel, who attended the Texas Rangers' home game against the Los Angeles Angels on Tuesday night, ended a 10-week stay in rehab Friday. He is expected at the Browns' offseason program that begins Monday. Thomas' comments echoed statements he made earlier this month that Manziel "probably lost a lot of trust among the guys" on the team.
Safety Donte Whitner did not disagree.
"I would say yes to that," Whitner said of losing trust. "I would think that he would say yes to that. The thing is, we commend him for what he did [entering rehab]. Nobody knew the actual things that were going on in his life but him and his family.
"So, to commend him, to be so young and take the initiative and do what he did, it can only help him as a person first and foremost and then as a football player."
"I just knew it was distracting his game, and it wasn't allowing him to be himself out on the field," linebacker Karlos Dansby said. "It wasn't allowing him to express himself the way we all saw him play at the collegiate level. Whatever he was dealing with was suppressing him. Him being able check himself in and try to get that relief, I think it was huge."
What do his teammates expect of Manziel now?
"I think it will be important for him when he comes back to prove to the team, to everybody in the organization that football is the most important thing in his life and he is willing to commit to it and make it the most important thing in his life," Thomas said. "Because to be a successful NFL quarterback, that's what you have to do.
"I think there was some doubt based on what he did last year if football was the most important thing. He's made some excellent strides already in the offseason kind of setting himself up."
Thomas said what matters more is what Manziel does through organized team activities, training camp and, ultimately, the season.
"[The offseason is] part of the journey," Thomas said, "but in the end it's what you do during the season. Certainly I think he's set himself up really nicely by the steps he's taken already to really prove that he can be the guy. Right now is kind of the start of the process.
"Like I said, what you do on Sundays is what you are judged by in this game."
"I believe that he'll come in, he'll earn our trust back, he's that type of guy," Whitner said. "He'll have to compete for his job. I believe he'll be up for that challenge. We will welcome him back with open arms."