Manziel, the 2012 Heisman Trophy who ran into plenty of issues off the field and a lack of NFL success on it, told reporters afterward he is determined to keep continuing his comeback.
"I'm ready to go," Manziel said. "I haven't felt this good in a long, long time, from a mental standpoint and a physical standpoint."
Manziel said he's off to Austin, Texas, on Wednesday to start the short-season developmental Spring League. Games will be held April 7 and April 12.
Manziel last played in the NFL in 2015. He was asked Tuesday about how he thought those in the NFL viewed him.
"I've blocked it off. I can't do anything. I can't stress about it," he said.
"All I can do is make sure I'm where I need to be, where I'm at mentally, where I'm at physically and when I get a chance to go to the Spring League, be in there doing the film stuff, getting back into the really, really, real football stuff.
"It's not just coming out and throwing. That's great. That's part of it. But that's step one. Then there's the film. There's the coverage. There's everything else that comes with being in the building. That's what the Spring League gives me a little bit of."
The Hamilton Tiger-Cats of the Canadian Football League hold Manziel's negotiating rights.
"If something pops up, it pops up," Manziel said of the NFL. "If not, and if I don't get the opportunity to go back, I'm going to go play in the CFL and things are going to be fine. And, one way or another, one day down the line, I'll get back to exactly where I want to be because I'm not going to stop until I do."
Manziel, the 22nd overall selection in the 2014 draft by the Cleveland, Manziel played 15 games for the Browns and completed 57 percent of his passes with seven touchdowns, seven interceptions and seven fumbles.
He had significant problems off the field.
He was investigated by Dallas police in 2016 for domestic violence against an ex-girlfriend, but the charges were dropped when he agreed to undergo counseling.
Manziel entered a rehabilitation center in 2015 and was suspended for the first four games of the 2016 season for violating the NFL's substance abuse policy.
Manziel, 25, also recently talked about dealing with bipolar disorder.
"I can't do what I want to do football-wise, if I don't do what I need to do mental health-wise," he said.
"If I'm not going to see a psychiatrist and a psychologist at least a couple of times a week, if I'm not going and taking my medicine every day, then I'm not the same person. And I see it. First things first.
"I can't be me without doing the necessary steps that I need to do to keep my head right. That's just a fact. It took me a while to overcome that and get where I felt like I was comfortable with it, but when I did, I started to see improvement in all aspects of my life.
"The people that I have around me, from my wife to my dad to my sister to all the people I have here with me -- my agent, my advisor, everybody -- I have a good team around me and I have cut off a lot of the leeches that have been around me in my life, and it was really needed."
Manziel thanked new Texas A&M coach Jimbo Fisher for giving him a chance to throw at Pro Day, where, in front of scouts from every NFL team, the former Aggies quarterback threw to the team's top NFL prospect -- wide receiver Christian Kirk. NFLDraftScout.com rates Kirk as the third-best receiver and the No. 32 overall prospect in the draft.
Manziel, who also threw at the University of San Diego's Pro Day last week, joked that he's done with these workouts.
"I'd like to officially announce I'm retiring from all Pro Days moving forward," he said. "I will not be doing any more."