After losing two veterans — tackle Jermon Bushrod and quarterback Chase Daniel — on the first day of free agency Tuesday, the New Orleans Saints worked to regroup by making headway in their efforts to upgrade their defense.

On Wednesday, Pittsburgh Steelers cornerback Keenan Lewis tweeted he was making a free-agent visit to the Saints training facility in Metairie and Jacksonville Jaguars cornerback Derek Cox reportedly was also scheduled to visit.

The name of former Philadelphia Eagles cornerback Nnamdi Asomugha, who was released Monday, was also linked Wednesday afternoon to the Saints by as one of five teams that are interested in his services.

Meanwhile, the Saints lost another member of their 2012 team when linebacker Jonathan Casillas agreed to a one-year contract with the Tampa Bay Bucs, and long snapper Justin Drescher, a restricted free agent who didn’t receive a tender offer from the Saints, agreed to a four-year deal to remain with the team.

Lewis, a New Orleans native and O. Perry Walker High School graduate, tweeted: “Taking a drive down Airline Dr. To visit with the New Orleans Saints!!!”

The Saints finished last in the NFL last season in allowing a league single-season record 7,042 total yards, and it was widely speculated they would target the front seven as they make the transition from a 4-3 alignment to a 3-4.

But the Saints could also use some help in the secondary as they ranked next-to-last against the pass in allowing 292.6 yards per game.

They also were hit for 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.

Lewis, who is rated as one of the top cornerbacks available in free agency, or Cox, who was on Tampa Bay’s radar over the weekend, could upgrade the position. Both were third-round picks in the 2009 draft.

Lewis excelled in his first year as a starter in 2012, and had 71 tackles while breaking up 23 passes for the Steelers. Cox is a four-year starter who had four interceptions in three of his four seasons with the Jaguars.

Before going to the Eagles in 2011, Asomugha was with the Oakland Raiders from 2003-10 — playing five seasons during that time for new Saints defensive coordinator Rob Ryan.

The Saints’ starters last season were Jabari Greer and Patrick Robinson, a first-round draft pick in 2010 who’s struggled at times during his three-year career.

Corey White, a fifth-round draft pick last spring, was settling in as a solid nickel back until a knee injury ended his rookie season early.

Casillas was a part-time starter after making the Saints roster as an undrafted free agent in 2009. He was limited to only 38 games and seven starts, however, because of injuries and missed the entire 2010 season with a foot injury suffered after he won a starting job in training camp.

Drescher, who joined the team midway through the 2010 season, was not tendered by the team last weekend when center Brian de la Puente and running back Chris Ivory were given second-round tenders at $2.023 million each.

If de la Puente or Ivory were to receive an offer from another team, the Saints would have a chance to match it and retain the player or receive a second-round draft pick as compensation.

The Saints’ other restricted free agent, linebacker Junior Galette, agreed to a three-year contract on Saturday.