Coleman is familiar with Buffalo's defense after playing in eight games with the Bills as an undrafted rookie last year. The Auburn product was then among the Buffalo's final cuts prior to the start of this season.
The move, announced by the Bills on Wednesday, comes a day after starting linebacker Shawne Merriman was placed on injured reserve due to a nagging Achilles tendon injury that will require surgery.
After being bothered by a nagging shoulder injury for the past month, Merriman's Achilles suddenly became a problem on the Thursday before the Bills' 27-24 loss to the Giants. Merriman missed that game, but he expressed confidence that he'd be able to return and not miss any significant time when the Bills came back from the bye.
In a statement released by his publicist, Merriman said the Achilles has become so aggravated it is in danger of rupturing.
"I have been advised that it would be in my best interest to undergo surgery as soon as possible in order to prevent a major injury," Merriman said. "I would like to thank all of my fans for their continued support on my road to a full recovery and am looking forward to getting back out on the field."
The Bills (4-2) return from their bye week off to prepare to "host" the Washington Redskins (3-3) on Sunday in Buffalo's annual home game at Toronto.
Information from The Associated Press was used in this report.