But during summer workouts, Brown went down with a knee injury. He said he was "lucky" it was just a partial tear to his ACL.
"It could have been worse," Brown said.
The 6-foot-1, 235-pound Brown missed all of fall camp and the first two games of the season. But he's almost 100 percent as the Cardinals head into Saturday's noon game against Florida International at Papa John's Cardinal Stadium.
Brown played some snaps last week in the second half against Kentucky and will get more reps this week against the Panthers.
"He's starting to get in shape and feeling pretty good about his body," U of L defensive coordinator Vance Bedford said. "He's still worried a little about that knee, but he's fine. And with him out there, I feel very confident.
"He's so very athletic. If you say do I want a fifth defensive back out there or Keith Brown, I will take Keith Brown every day. You will see him more."
Brown, who started five games and played in 11 as a true freshman last season, said he's been working hard to try and get into playing shape.
"I'm overwhelmed to be back honestly, because I was the first person to try the surgery I had so nobody knew the exact time that I would be back," Brown said. "I just feel lucky and am ready to be back."
Brown said he feels like he can step into a role as more of a leader, knowing he brings a lot of "intensity and physicality," to the defense.
"I'm stepping into the role as a leader, but I'm still learning from guys like Preston (Brown) and Teddy (Bridgewater)," he said. "They are teaching me what it takes to become a leader. I want to continue where I started last year, and build upon that."
Brown had a season-best 13 tackles in the win against Cincinnati and registered 12 in the Cardinals' win at Pittsburgh.
Now, he's just glad to be back on the field.
"My coaches, trainers, and parents all played a role in me coming back, and just keeping a positive mindset," he said. "I'm excited."