The team also signed tight end Andrew Szczerba to the practice squad.
The moves came a day after Atlanta released defensive end Ray Edwards.
Toone, a 2010 seventh-round draft pick by Detroit, joined the Falcons in the offseason as a free agent. He didn't make the active roster to open the season but had three receptions, including a 39-yard touchdown catch, in the preseason.
Coffman opened this season on Atlanta's practice squad.
Gallarda, a strong blocker, was a backup in all nine games this season. He hurt his shoulder in Sunday's loss in New Orleans.
http://accesswdun.com/article/2012/11/255166