The 2011Kansas City Chiefsseason was the franchise's 42nd season in the National Football League, the 52nd overall and the third under the head coach/general manager tandem of Todd Haley and Scott Pioli. The Chiefs failed to improve on their 10–6 record in 2010. On July 25, the NFLPA and the NFL owners agreed on a new collective bargaining agreement. The Chiefs training camp began on July 29 in St. Joseph, MO. The Chiefs played their first preseason game on August 12 against the Tampa Bay Buccaneers. On September 11, the Chiefs opened their regular season against the Buffalo Bills. Despite entering the season with high expectations, even with their tough schedule, they did not earn their first win until Week 4 against the Minnesota Vikings and finished the first quarter of the season with a disappointing 1–3 record. After starting the season 5–8, head coach Todd Haley was fired after a 37–10 loss to the New York Jets and replaced by defensive coordinator Romeo Crennel on an interim basis for the remainder of the season. One bright spot of the season is the first game after Crennel took over as interim head coach; an upset win against the then 13–0 Green Bay Packers to ruin their perfect season hopes.
Hoping to snap a three-game losing streak, the Chiefs went home for a Week 12 Sunday night duel with the Pittsburgh Steelers. Kansas City delivered the game's first punch in the opening quarter with a 41-yard field goal from kicker Ryan Succop. The Steelers would answer in the second quarter with kicker Shaun Suisham getting a 21-yard field goal, followed by quarterback Ben Roethlisberger completing a 2-yard touchdown pass to tight end Weslye Saunders. The Chiefs would reply with a 49-yard field goal from Succop, but Pittsburgh would close out the half with Suisham booting a 49-yard field goal. After a scoreless third quarter, Kansas City began to chip away at their deficit in the fourth quarter with a 40-yard field goal from Succop. However, the Steelers' defense held on to preserve the win. With the loss, the Chiefs fell to 4–7.
In one of the biggest upsets of the year, the Chiefs beat the heavily favored Green Bay Packers, ending their hopes of a perfect season. The Chiefs defense held Packers quarterback Aaron Rodgers to 235 yards, a 48.6% completion percentage, and his only game of the season without multiple passing touchdowns in what was Roger's worse game statistically of the season. This was the last home victory for Kansas City until Week 13 of the 2012 season when they defeated the Carolina Panthers one day after the Jovan Belcher tragedy.
