"I think last year pretty much humbled me," Gilbert said Thursday at the team's offseason practice. "A lot."
Just two weeks ago, veteran safety Donte Whitner said that Gilbert had a "disastrous" rookie season. In the final month Whitner and other teammates unloaded on Gilbert, with Whitner saying the eighth overall pick in the draft had to stop acting like a kid.
The situation got worse. At the season finale in Baltimore, Gilbert arrived late for a meeting at the team hotel and was deactivated for the game, a move coach Mike Pettine said was essentially a suspension.
Gilbert and Johnny Manziel, the team's other 2014 first-round pick, watched the game in the locker room -- a move not unlike being sent inside from recess.
Gilbert said that last game's experience combined with some pointed heart-to-heart talks with the coaches and general manager Ray Farmer after the season convinced him he had "to grow up."
Coach Mike Pettine said at the scouting combine that Gilbert had a personal issue he was dealing with last season. Gilbert said Thursday there was no issue, then admitted there was something, but he didn't want to talk about it.
In the offseason, Gilbert spent a lot of time with cornerback Joe Haden, a pairing the team thought would be good for the young cornerback. In that time, Gilbert got stronger, but also grew in his understanding of what it takes to be a pro.
"I wish it hadn't happened that way," Gilbert said of the ugly season finale. "But I think it really helped me."
Gilbert admitted the public criticism at the end of last season stung, but the eighth overall pick in the draft said now "there are no hard feelings toward anyone."
The Browns have spoken positively about Gilbert's approach and on-field work this offseason, and he said the team will give him a chance to return kickoffs this season -- a possibility that made his eyes light up.
During his interview, Gilbert seemed more comfortable, relaxed and confident. He said he agreed "100 percent" with the criticism he heard in postseason one-on-one discussions.
"Talking about how I had to grow up, how I had some maturing to do," he said. "I kind of took that to heart."
He said his "actions" are the only way he can respond.
"That's the best I can do," he said. "Prove it every day."