TUSCALOOSA, Ala. – Falcons coach Dan Quinn didn't like how his team was pushed around at times last season.

So, he went out and signed one of the best centers in the league in former Cleveland Brown Alex Mack on Monday.

Mack is set to sign a five-year contract that’s worth $45 million with $28.5 of the money guaranteed, according to overthecap.com.

“We had a good plan going into the offseason with regard to free agency,” Quinn said via phone. “Now, we’re getting a chance to work that plan. We wanted to have a focus on the line of scrimmage.”

Mack, 30, a three-time Pro Bowler will step into the starting lineup and serve as quarterback Matt Ryan’s chief protector. It’s a role the Falcons failed to adequately fill with the forced retirement of Todd McClure after the 2012 season.

“In my opinion, the best player available at the position, for us at center, was Alex Mack,” Quinn said. “I’m pumped to have Alex on board.”

In addition to signing Mack, the Falcons added backup quarterback Matt Schaub, who’s in the twilight of his career, and defensive end Derrick Shelby, a former reserve with the Miami Dolphins.

Shelby, 27, agreed to a four-year deal potentially worth $21 million.

They also released defensive tackle Paul Soliai and have a visit scheduled with wide receiver Mohamed Sanu. He’s a candidate to fill the vacancy created by the release of Roddy White, the franchise’s all-time leading receiver.

Schaub was originally drafted by the Falcons in the third round of the 2004 draft. He served as Micahel Vick’s backup before being traded to the Houston Texans in 2007, where he played for Falcons offensive coordinator Kyle Shanahan.

He spent last season in Baltimore as a reserve. Schaub has played 141 games and made 92 starts. He has a 47-45 record as a starter. He’ll compete with last season’s backup Sean Renfree.

“He has experience certainly in the scheme and will add to that group,” Quinn said.

But the Falcons were most elated about adding Mack.

Over the past three seasons, Ryan has been sacked 105 times. In 2013, he was sacked (44), hurried (45) or hit (206) a whopping 295 plays. Over his first six seasons with the McClure at center, Ryan was sacked 113 times.

“The proven ability when you put the tape on,” Quinn said. “Not only is he tough and durable, he’s got the speed to climb to the next level to cut guys off. Not only in protection can he handled it one-on-one, but just directing the traffic, the knowledge and toughness that he brings. I love the way that he competes. It was kind of a combination of those things that make him such a unique player.”

Quinn has changed the team’s free agency plan of shopping for players at the mid-level of free agency and for bargains. However, he doesn’t believe the outlay for Mack will hamper the team’s effort to sign a wide receiver, an offensive guard and linebacker in free agency.

“We still have a good plan that we are still working through with some of the other players to add to the team,” Quinn said. “We don’t feel like in any way hamstrung or limited in that fashion. Alex is certainly an important piece to what we are doing. But certainly there is other work (to be done) over the next few days.”

The Falcons are competing against New England to sign Sanu. They lost battles for former Seattle guard J.R. Sweezy, who signed with Tampa Bay, and for linebacker Danny Trevathan, who signed with Chicago.

“I’m pumped to have him come down,” Quinn said of Sanu. “I think it’s a terrific fit. There are lots of reasons like getting a chance to play with guys like Julio Jones and Matt Ryan and the culture that we have in the locker room with the players.”