The deal is for one year, according to a source.
"Just another opportunity to continue to compete," Quinn said of Long's signing. "Look forward to having Jake here.
"I am excited to have him compete -- his toughness. For a guy, 'Yeah, I just want a chance to compete.' When a guy talks to you like that, you certainly have a lot of respect for how he goes about his business. So, we're excited to have him here; get him up to speed as fast as we can. And then we'll kind of cross that bridge in terms of where and [when] after that.
Long worked out twice for the Falcons. He recently received full medical clearance after tearing the ACL in his right knee for the second time last season. Long suffered the injury in the seventh game a year ago while playing for the St. Louis Rams.
"That was part of the process -- for him to have as much time as he needed to get healthy and to get ready," Quinn said. "Just looking forward to him being a part of the group. [General manager Thomas Dimitroff] and I, we love the toughness and the attitude that goes along with that position. He certainly has it."
Quinn does not expect Long to be ready to play against the New York Giants on Sunday. The Giants also expressed interest in Long during the free-agent process.
Long, 30, has finished each of the past four seasons on injured reserve. He's also had torn biceps and triceps injuries to go with the multiple ACL tears. Long started all 96 games he's played in through seven seasons with the Dolphins and Rams.
Another benefit tofigning Long is his ability to mentor young players such as Matthews and Schraeder, both of whom played well in Monday night's 26-24 season-opening win over the Philadelphia Eagles. Matthews is feeling no ill effects from a back strain suffered in the preseason, while Schraeder is doing a better job working with his hands.
Falcons nose tackle Paul Soliai, a teammate of Long's in Miami, talked about the presence Long brings to the locker room.
"He's a hardworking guy and a great player," Soliai said. "He didn't have to adapt when he came into the league. He came in and he knew how to act like a professional.
"I hate for any NFL player to go through injuries. He was a good teammate in Miami. The time I was there, the only thing I could tell you about J-Long is he would try to outwork whoever he plays against. I know he's always ready to come to work."
To make room for Long, the Falcons released veteran safety Charles Godfrey. The other offensive tackles on the 53-man roster are veteran Tyler Polumbus and Bryce Harris. Former starting tackle Lamar Holmes remains on the physically unable to perform list after breaking his foot in minicamp.