Leigh Torrence was waived by the Redskins to make room for DeAngelo Hall.
From the article linked, Torrence is a 26 year old CB that was ascending and viewed as getting better and better with each game and an excellent special teams player. He was also extremely popular in the locker room and many teammates expressed extreme shock that he was released.
Torrence (5 feet 11, 179 pounds) was signed as a free agent by Washington in 2006 after spending 2005 with Atlanta. The Stanford grad played regularly last season with cornerback Carlos Rogers injured, and had been utilized often in recent weeks in particular again with Springs suffering from a calf injury (he is expected back for the next game, against Dallas).
The Chiefs are hurting for a good nickel CB with Leggett getting taken advantage of and Surtain frequently hurt. This guy might be a good pickup. Plus he's been in the league a few years and isn't brand new to the NFL.