First, who's leaving: DL Atiyyah Ellison. He was signed last week before the Chiefs played the Jaguars. Ellison previously played for the Jaguars but Todd Haley indicated last week that his signing was not just to get information on Jacksonville.
Second, who's coming back: WR Jeremy Horne. He returns to the practice squad. He was waived last week before the Jaguars game in place of WR Verran Tucker, who was promoted from the practice squad.
Third, who's the new guy: LB Mark Simoneau. He was a third round pick in 2000 out of Kansas State. He's played for the Falcons, Eagles and Saints. He'll be a special teams guy in Kansas City. Simoneau spent the 2009 season on IR with a torn triceps muscle. The Chiefs worked him out about a month ago.
That wraps up the Chiefs roster moves to this point in Week 8. It leaves the Chiefs with a full practice squad and a full active roster.