A former second-round draft choice out of the University of Miami, McIntosh played six seasons for the Washington Redskins and started 69 regular-season games at both inside and outside linebacker.
He recorded 80-plus tackles in four straight seasons and had a career-best 110 in 2010. During his six-year career, the 29-year-old linebacker has 471 tackles, eight forced fumbles, eight sacks and three interceptions.
McIntosh returned to the Redskins last season on a one-year deal, but eventually lost his starting spot to second-year linebacker Perry Riley.
The free agent also is known to have visited the Miami Dolphins.
Kehl, a four-year veteran out of BYU, spent the majority of the past two seasons with the St. Louis Rams, where he made two starts while also playing a key role on special teams. He broke into the league with the New York Giants in 2008 and remained in New York until early in the 2010 season. Kehl also made an official visit to the Dolphins last week.
Diles was a former starter for the Houston Texans, where he spent time at both strong side and weak side linebacker. He started 30 games from 2008 to 2010, and recorded a career-high 82 tackles during his final season in Houston.
The Bears are in the market for experienced depth at linebacker behind veteran starters Brian Urlacher, Lance Briggs and Nick Roach. Rounding out the depth chart at the position are two former undrafted rookie free agents, Dom DeCicco and Patrick Trahan; former St. Louis seventh-round selection Jabara Williams; the Bears' 2011 sixth-round pick, J.T. Thomas, plus newly signed special teams ace Blake Costanzo.
Thomas spent his entire rookie season on injured reserve and was arrested in the offseason on a misdemeanor drug possession charge.
Urlacher and Roach both have one year remaining on their current contracts. Briggs recently was rewarded with an extension and is under contract through 2014.