FLOWERY BRANCH — In four seasons under coach Mike Smith, the Falcons’ pass defense has consistently been the lowest-ranking phase of the team and has failed them in playoff games against elite quarterbacks Kurt Warner, Aaron Rodgers and Eli Manning.

On Tuesday, the Falcons’ top cornerback against the pass, Brent Grimes, signed his one-year, $10.281 million franchise tender and trade talks continued with the Philadelphia Eagles to land one of the top ball-hawks in the game, Asante Samuel.

Working out compensation with the Eagles was not an issue, but crunching the numbers to fit Samuel’s contract under the salary cap was the key holdup.

“As far as Asante Samuel is concerned, I can only speak from having played against him a number of times, and I know that he’s been extremely difficult to play against,” Falcons quarterback Matt Ryan said.

Falcons linebacker Sean Weatherspoon, who will take over the signal-calling duties on third downs for the defense in 2012, would welcome Samuel to the unit.

“I think he’s a great player,” Weatherspoon said. “We played against them the last few years and we saw what he could do. He’s definitely a player that I think would improve anyone’s defense.”

Grimes did not attend the start of the Falcons’ voluntary offseason training program Monday. It was unclear if both sides will continue to negotiate toward a long-term deal. In early March, the Falcons placed the franchise tag on Grimes, which guaranteed that he would make the average salary of the top five cornerbacks in the league.

Grimes did not immediately sign the franchise tag, and his representatives stated that they wanted to work out a long-term deal.

Samuel, 31, was with the Patriots when Falcons general manager Thomas Dimitroff was the director of college scouting. Dimitroff coveted Samuel last season, but the Eagles’ asking price — a second-round pick — was considered too steep at the time.

The Eagles reportedly want only a late-round draft pick, perhaps the Falcons’ non-compensatory seventh-rounder.

Last season, the Falcons ranked 20th against the pass as they gave up 236.6 yards passing per game. In 2010, they ranked 22nd (226.6). In 2009, 28th (241.9) and 21st (220.4) in 2008.

The defensive coaching staff in the secondary has turned over. Emmitt Thomas and Alvin Reynolds were replaced by Tim Lewis and Joe Danna. Thomas was not re-signed after the 2008 season, and Reynolds was fired after this past season. Also, defensive coordinator Brian VanGorder returned to the college game in January and was replaced by Mike Nolan.

The combination of new coaches, the return of Grimes and the possible addition of Samuel should help the pass coverage.

Grimes and Dunta Robinson were the starting cornerbacks for much of the past two seasons. The Falcons have had trouble finding a third cornerback.

Over the past two seasons, Brian Williams, Christopher Owens, Dominique Franks and Kelvin Hayden all played the nickel position.

If the Falcons land Samuel they would have a solid trio of cornerbacks.

Smith has noted that the nickel back is considered a starter because the team plays more downs in their nickel package than they do in their base defense.

Samuel, 5-foot-10 and 185 pounds, was set to make $9.9 million in base salary in 2012 and $11.4 million in 2013.

He was drafted by the Patriots in the fourth round (120th overall) of the 2003 draft out of Central Florida.