METAIRIE, La. -- A.J. Klein knew what he was risking -- on social media, anyway -- by leaving the Carolina Panthers for the rival New Orleans Saints in free agency.

“Oh my goodness,” Klein said when asked what was the most interesting grief he received for switching allegiances. “It’s hard. I mean, every fan is very passionate about the team they choose to root for. The hard part is being able to separate those emotions. And for us as a player every day, it sounds bad, but it’s a business for us and this is my professional career and that’s the way I approach it.

“Yes, I have emotional ties to Carolina. But when opportunity knocks, you have to take advantage of the opportunity. So for fans that are a little angry that I left or feel that I’m a traitor, I don’t want to break any hearts. But it is what it is and it’s a business at the end of the day.”

In this case more than most, however, even the most die-hard Panthers fans can't blame Klein.

The 25-year-old linebacker will finally get a full-time starting opportunity after spending the past four years stuck behind Luke Kuechly and Thomas Davis, arguably the best linebacker duo in the NFL.

If ever there was a player destined to switch teams in free agency, it’s Klein, who played very well over those four years whenever needed because of injuries to Kuechly or Davis. Klein, who called them “great dudes” and “good friends of mine” started a total of 23 games in four years, with 146 tackles, four sacks, four forced fumbles and an interception.

“Do I think I could’ve played? Yes. Did that time help me develop as a player? Most definitely,” said Klein, who was drafted in the fifth round out of Iowa State in 2013. “It was a tough situation to come into, knowing that I'd have to compete. But it also made me a better football player, made me a better person, and I definitely learned a lot. And I think my first four years have been very well spent.

“I know I wanted the opportunity to start. But it wasn't necessarily frustrating because you can't be frustrated when you're playing behind two all-pros.”

The fact that Klein wound up with a heated division rival also makes sense -- because the Saints appreciate as well as anybody how well Klein played whenever he got a chance to sneak out of the shadows. New Orleans gave Klein a contract that will pay him like a proven starter -- $15 million over three years, with $9.4 million in guarantees.

Klein (6-foot-1, 240 pounds) will likely be penciled in as the Saints’ middle linebacker (making him their fifth in four seasons). But the Saints also have veteran Craig Robertson, who played well in that role last year, and former first-round pick Stephone Anthony. And they have been talking with free agent linebacker Manti Te'o. So the versatile Klein knows his role could be flexible.

“I think there probably will be an opportunity [to start at middle linebacker], but at the end of the day what’s said now can change in a heartbeat. And that’s just the way the business goes with personnel changes and hopefully not any injuries,” Klein said. “So I think the expectation that they have for me is to be prepared to play any one of those three spots. Do I have a preference? I’ve played more Sam and Mike then I have Will, so yeah that could be a preference for me. But at the end of the day I’m very fluid, and I’ll go wherever they need me to go, and that’s what I’ve been doing the past four years in Carolina.”

No matter where he lines up, Klein will get an opportunity to do something he once got chastised for -- going full-speed after Panthers quarterback Cam Newton twice a year.

“I fondly remember back when I was a rookie coming a little bit too close, and I got pulled aside by Coach and he basically gave me the lowdown of how things go,” Klein said with a laugh. “But I’ve gotten to know Cam really well over the past four years, and he’s a great competitor. And I’m obviously looking forward to the opportunity to compete against him.

"He’s a great athlete, big bodied. I don’t think there's anybody in the NFL that wouldn’t want to be able to sack Cam or tackle him, so it’s gonna be fun to compete against him.”