Two years ago, six weeks into the 2011 season, Jason Campbell was having one of the better years of his career. Then, against the Browns, of all teams, Campbell scrambled out of the pocket and was gang-tackled by Chris Gocong and Scott Fujita, breaking his collarbone. He lay on the grass, looking up, and before he knew it, the Oakland Raiders had traded for Carson Palmer. Campbell was no longer their starting quarterback and his career had taken a turn for the worse. The Raiders were on their way to a 4-2 start when Campbell was hurt. Campbell, 31, served in a backup role for the Chicago Bears last season and then signed with the Browns to push incumbent starter Brandon Weeden. The injury in Oakland taught him the harsh realities of the NFL. “I was having the best season of my career,” Campbell said Wednesday after the second practice of voluntary minicamp. “To wake up and knowing there’s been a trade and I’m not starting anymore, it was a tough pill to swallow. But at the same time, it taught me a lot about the game and understanding there is a business side of it. “You can’t get your emotions so caught up in the game that you forget to continue to compete and continue to push yourself and grow and grow. Sometimes life is about adversity. It’s always how you respond, not how you give in to it. … If you get down, you may miss your next opportunity. That’s always been my mindset.” The Browns are his next opportunity. Campbell signed a two-year, $3.75 million contract in March, with $500,000 of it guaranteed. It’s a team-friendly deal for a quarterback who’s expected to light a fire under Weeden, and should he falter, be able to take control. Campbell, who has a career record of 31-40 as a starter, sounds as if he’ll accept whatever role he’s given. “My role, I have to adapt to change,” he said. “Having to do that in my past has prepared me. There are things you can’t control. I’ve learned not to worry about those things but worry about how can I get better as a player and what I can do more to help my teammates. It’s not about you in his business. It’s about the team.”