The Saints made a significant move to upgrade their 32nd-ranked defense Thursday with the signing of unrestricted free agent cornerback Keenan Lewis to a five-year contract worth a reported $26 million.

Lewis, 26, played his first four NFL seasons with the Pittsburgh Steelers, who selected him in the third round of the 2009 draft.

Lewis, a New Orleans native, played his high school football for O. Perry Walker before going on to play for former Saints secondary coach Mike Riley at Oregon State.

The 6-foot-1, 208-pound Lewis was a starter for the Steelers for the first time in 2012, but produced a breakthrough season in which he had 71 total tackles and broke up an NFL-leading 16 passes.

Even though he was a starter for just one season, Lewis was one of the top cornerbacks available when the free-agency signing period began Tuesday afternoon. He tweeted Wednesday that he was going to visit the Saints at their Metairie training facility.

“I’m very excited to be able to come back to my hometown,” Lewis said in a Saints news release. “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.”

“We are excited to be able to add a player of Keenan’s ability to our defense,” Saints General Manager Mickey Loomis said in the release. “He was a top free agent target for us and I know that he is very excited to be able to come home to play football.”

The Saints set an NFL single-season record in allowing 7,042 total yards last season, but they also ranked next-to-last against the pass in allowing 292.6 yards per game.

They also gave up 31 touchdown passes, just two off the league lead, as opposing quarterbacks completed 61.5 percent of their passes and compiled a passer rating of 93.8.