Johnny Manziel: It's about action

— -- BEREA, Ohio -- Johnny Manziel said reports of him throwing a party in Cleveland on Friday night are "100 percent false" but acknowledged that he went out with a few friends and was not at the team's Saturday walk-through and treatment sessions at the appropriate time.

Manziel said he's in prove-it mode, and nothing he says anymore will convince people that he's ready to play quarterback for the Browns unless he shows it over the offseason and in 2015.

"It's about action," Manziel said. "It's about being accountable and doing what I'm gonna say instead of looking like a jackass."

Browns coach Mike Pettine said Monday that the future of the Browns' quarterback position is "muddy at best," but that Manziel's off-the-field behavior and all the social media attention that goes with it is a factor, but not the determining factor.

"At some point the talk is cheap," Pettine said. "He's gotten himself to the point with me that his actions are much more important than what he says."

Manziel said he was "extremely upset" Saturday morning that he let his teammates down and needs to be accountable. Manziel was on injured reserve and did not need to participate in the walk-through before the Ravens game, but he could have shown up for support and been on time for treatment on his hamstring.

He said that he let his guard down because he wasn't part of Sunday's game plan but shouldn't have. Manziel said he was not with Josh Gordon -- who was suspended for missing the walk-through as an active player -- on Friday night but saw him earlier in the day and was not responsible for Gordon's absence. Manziel said he went out with three friends from his hometown of Kerrville, Texas.

Manziel stressed on Tuesday to the local media he wanted to be "the guy" for the franchise, to take ownership of the job and take this offseason more seriously than last. He said Monday that he had no doubts about his plans when he said those things and that he just made a mistake.

He knows his actions aren't reflecting his words when he stays out too late and doesn't get up for team activities. Manziel looked around to the large media scrum and said, "I brought these cameras and all these people to the locker room right now" because of the unfair distractions he brought to the team. He apologized to team veterans, who were vocal after Sunday's 20-10 loss to Baltimore that the organization needs players who are all-in.

"It sucks because of the perception I've based around myself -- I've done this to myself -- that that was allowed to be reported and people are just allowed to nod their head and act like that went on," Manziel said.

Added Manziel: "Either I'm going to learn or I'm going to be finding something else to do."

Players hope Manziel gets it.

Left tackle Joe Thomas said he's seen NFL talent from Manziel either in practices or from his Texas A&M days, but he adds, "You'd expect a middle-schooler to show up on time. Why can't we expect NFL players to show up on time?"

Quarterback Brian Hoyer said he's had talks with Manziel in the past and believes "it's up to him" whether he makes the necessary changes. Hoyer acknowledges that process can take time considering Manziel's age (he turned 22 this month).

Right guard John Greco says he's a fan of second chances and doesn't know if it's "too little, too late" for the rookie. Manziel said this offseason is "very critical" and all he wants is a chance after "[I] really look in the mirror."

"I think he knows now things will have to change for him," Greco said. "I would assume that when we come back he'll be focused on trying to become the starter and a leader."

ESPN.com Browns reporter Pat McManamon contributed to this report.