Lewis was a third-round pick by the Steelers out of Oregon State in the 2009 NFL Draft. He struggled to get a lot of playing time in his first two seasons, but played in every game in 2011 and 2012, finally breaking into the starting lineup this past season. In his first four seasons in the league, Lewis has made 120 tackles, picked off one pass and broke up 29 others.
Lewis was considered one of the top available corners heading into free agency, not just because of his skill, but because of his price, as he likely wouldn't be nearly as expensive as some other big-name free agents.
Lewis, a New Orleans native, said that he's excited to come back to his hometown to play football.
"I'm very excited to be able to come back to my hometown," Lewis said. "Having grown up here I understand the passion that the fans have for the Saints and I'm blessed to be able to have the chance to play in front of them here in the future. I had a great visit with the Saints and am thankful for the time I spent with the Pittsburgh Steelers and wish them continued success."
Saints general manager, Mickey Loomis, said in a press conference on Thursday that the team is excited to add a player "of Keenan's ability" to its defense, saying that Lewis was a top target for the Saints in free agency.
The Saints had the second-worst passing defense in the league through the 2012 regular season, giving up an average of 292.6 yards per game through the air. Adding new and talented pieces to their secondary should help, especially when they face Matt Ryan, Cam Newton and Josh Freeman twice every season.