3:21pm: The Falcons officially announced the signing.
“We knew we needed to add an established presence along our offensive line,” said general manager Thomas Dimitroff. “Alex is a three-time pro bowler and is an ideal scheme fit for our offense. We understand the importance of solidifying the center position and we have been able to do that today. We are pleased to be able to add Alex to our roster and believe he will be an anchor to our line.”
12;26pm: Mack has agreed to sign with the Falcons on a five-year deal, per Ian Rapoport of NFL.com (on Twitter).
12:20pm: If he signs, Mack’s deal with the Falcons would pay him an average of $9.5MM, per Peter King of SI (on Twitter). Mack could have made $500K more per season with Cleveland, but he is leaning towards the Falcons because of a few factors, including the presence of offensive coordinator Kyle Shanahan.
11:33am: The Falcons are closing in on an agreement for Mack, according to Adam Schefter of ESPN.com, who cautions (via Twitter) that nothing is done yet.
9:48am: The Falcons are the frontrunners for center Alex Mack, Michael Silver of NFL Network tweets. The Browns, he adds, could make a late push to keep him. Earlier this week it was reported that Atlanta had “extensive interest” in Mack. 
Mack voided the final three years on his contract with the Browns earlier this month. Still, he indicated that he would be open to a Cleveland return. Mack stands as the top center on the free agent market and will aim to exceed $10MM+ per year on a new deal.
Mack, 30, has been one of the NFL’s most reliable centers since he entered the league in 2009. The veteran lineman has been Cleveland’s full-time starter since joining the team, starting all 16 regular-season games for the franchise in all but one of his seven NFL seasons. He has also earned three Pro Bowl nods.
Two years ago, when Mack first became eligible for free agency, the Browns used their transition tag on the center, who then signed a five-year, $42MM offer sheet with the Jaguars. Cleveland ultimately took advantage of the right of first refusal and matched the offer, but since the language of the contract included an opt-out for this winter, it was essentially a two-year deal rather than a five-year pact. This time around, the Jags reportedly do not plan on making a play for Mack.
Photo courtesy of USA Today Sports Images.
Nice get for the Falcons. Plenty of skill players on offense. Just need some protection for Ryan and they should be considerably better/more consistent on that side of the ball. Defense though??? Still needs some serious work.