The Falcons have been busy getting ready for the start of the NFL’s new business year, which begins at 4 p.m. Tuesday.

On Saturday, they agreed to terms with linebacker Lofa Tatupu, 29, a three-time Pro Bowler and one-time All-Pro, a move that basically signaled that linebacker Curtis Lofton will become a free agent.

In addition to securing Tatupu, with a two-year deal, the Falcons re-negotiated cornerback Dunta Robinson’s contract, signed offensive guard Vince Manuwai and re-signed three veterans — defensive end Kroy Biermann, safety Thomas DeCoud and running back Jason Snelling — over the past week.

“They have a great quarterback and a running back,” said Manuwai, who sat out last season after playing eight seasons in Jacksonville. “As an [offensive] lineman, this is a good situation.”

On Friday, the Falcons worked out Tatupu, who’s 6-foot, 250 pounds. The former Seattle linebacker did not play last season because of injury problems.

He will compete with second-year man Akeem Dent for the starting spot. The Falcons could use Dent in running situations and Tatupu on third downs.

The Falcons were ranked 29th in the NFL in third-down defense last season. Tatupu has 10 career interceptions.

Tatupu has a history of knee and concussion problems. He did not play in the league last season, reportedly because of his knee problems.

Robinson re-negotiated his contract with the team to provide them with $1.55 million in salary-cap space in 2012. On Jan. 25, Robinson’s cap-value number for 2012 was $7.55 million.

Manuwai, 6-foot-2, 335 pounds, played left guard in 111 games and started in 105. He said the Falcons want him for their right guard position.

Manuwai was a solid run blocker, who helped to power the Jaguars’ run game for running backs Fred Taylor and Maurice Jones-Drew.

He suffered a torn tendon in his ankle during the lockout and wasn’t ready to play when it ended.

Last season, the Falcons mainly used Garrett Reynolds and Joe Hawley at right guard. Also, Mike Johnson, who missed most of last season with a foot injury, will compete for the spot.

Manuwai played under current Falcons offensive coordinator Dirk Koetter for four seasons from 2007-10 when Koetter served as the Jaguars' offensive coordinator.

“It’s awesome because I know the offense already,” Manuwai said. “They just wanted to see me work out and make sure that I had no problems. They made the first offer, and that was it. I didn’t want to worry about looking somewhere else. To me, it wasn’t about the money.”