Sources: Keith Butler to join Colts' staff

Not only do the Indianapolis Colts plan to add former Steelers offensive coordinator Bruce Arians to their staff, but Indianapolis also plans to hire Keith Butler, Pittsburgh's linebackers coach, as its defensive coordinator, according to league sources.

Butler is planning to fly to Indianapolis on Tuesday to review and sign the contract that will make him a part of former Ravens defensive coordinator and current Colts head coach Chuck Pagano's staff.

Arians is scheduled to fly to Indianapolis on Monday to review and sign the contract. The Steelers had said he "retired" from his post but he confirmed last week that the team actually let his contract expire and he was still listening to coaching offers.

Butler's contract with the Steelers expired after this season. Pittsburgh did not want to lose him, but Butler wanted to be a defensive coordinator and Steelers defensive coordinator Dick LeBeau will be back again next season.

The 55-year-old Butler joined the Steelers before the 2003 season. Butler, Arians and Pagano were all part of then-Cleveland Browns coach Butch Davis' staff when he took that job in 2001.

Adam Schefter is ESPN's NFL Insider.