The Falcons had discussed adding Osi Umenyiora since early February. They knew his blazing pass rushes off the edge of the defense could help on the field.

In addition to valuing his football prowess, Falcons general manager Thomas Dimitroff and coach Mike Smith had to get comfortable with the notion of him fitting into the locker room and not becoming a disruptive force.

Smith believes that victories on Sunday start with a harmonious locker room.

Umenyiora had to overcome some misconceptions about his character and a scathing affidavit that was made public during the bitter labor fight between the NFL and the union during the lockout of 2011.

In addition to complaining about his contract during his stay with the Giants, he ripped Giants general manager Jerry Reese in the affidavit and called him a “liar.”

Umenyiora and Reese have patched things up, and the Falcons’ background check came back with glowing reports, which included talking to their secondary coach Tim Lewis, who coached Umenyiora when he was with the Giants from 2004-06.

“If it wasn’t for (Reese) I probably wouldn’t even be here now because obviously the team did a comprehensive amount of research on me, on my background, because of some of the things that have been reported,” Umenyiora said. “They wanted to know what type of person that I was. Obviously, they had to talk to Jerry Reese as well as my coach, and they had nothing but positive things to say.”

Umenyiora regrets that the affidavit became public.

“(The union) came to me and said in ‘what way did the lockout affect you,’” Umenyiora said. “Unfortunately, it was leaked, but that wasn’t supposed to get out there.”

Umenyiora signed a two-year, incentive-laden contract with an average $4.25 million base package. He could make up to $12 million on the deal. Umenyiora’s 75 career sacks rank 10th among active players.

He was drafted in the second round of the 2003 draft and played on two Super Bowl championship teams with the Giants. He was mentored by defensive end Michael Strahan and plans to pass along his teachings to the Falcons.

“I don’t think you can ever discount that,” Umenyiora said about the Super Bowl experience he brings. “Michael Strahan had been to a Super Bowl before, and they lost. Going into our situation, he was always there to tell us ‘you can’t do this’ or ‘you can do that, but you should do it this way’ or ‘this is why we lost.’”

Umenyiora, whose playing time decreased over the past two seasons, believes he can still play at a high level. Also, he addressed some of his critics, who contend that he doesn’t play well against the run.

“That’s mythology,” Umenyiora said. “It’s a (false) legend. (The Falcons) addressed that themselves. … Overall, I’m a very good run defender, and I look forward to continuing that.”

The Falcons will count on Umenyiora to replace John Abraham, who had 34.4 percent (10 of 29) of the team’s sacks last season. They also have defensive ends Kroy Biermann, Cliff Matthews, Jonathan Massaquoi and hybrid defensive end/tackle Jonathan Babineaux.

Last season under defensive coordinator Mike Nolan, the ends also were used as linebackers in 3-4 alignments and were required to drop into coverage.

Abraham flip-flopped from right end to left end on occasion over his tenure with the team.

“I’ve been primarily a right end, but earlier in my career I played left,” Umenyiora said.

He met with defensive line coach Ray Hamilton and did some film study of the defense.

When the Falcons open minicamp in April, Umenyiora may have to make amends with some of the offensive linemen. Before two teams faced off in the 2012 playoffs, Giants defensive end Justin Tuck referred to the linemen as “dirt bags.”

“I’m just happy to be a part of this team, and I’m going to encourage them to be as dirty as possible and to keep doing what they are doing,” Umenyiora said. “It’s worked very well for them.”