Think of it this way. Nearly every team is going to bring in more undrafted free agents each off-season than they are drafted players. Kansas City’s roster currently consists of 42 such players, which represents 53.8% of the players under contract to play for the Chiefs right now. Specific to 2010, the Chiefs currently have 11 undrafted rookies signed and chose seven players through the draft.
While draft classes are subject to grades, many of the sixth and seventh round picks are beaten out by the non-graded, undrafted class of players. The rookie free agents who make the team are often the guys who are asked to perform on special teams and offensive/defensive sub-packages (see Jovan Belcher for KC in 2009).
Another good read from Josh Looney at KCChiefs.com