On September 27, 2010, Mannelly broke Steve McMichael's Chicago Bears record for most games played as a Bear, with 192 (the record now stands at 245, at the time of his retirement he was tied for 43rd most in NFL history). In a 2011 game against the San Diego Chargers, Mannelly ruptured his ACL, and was placed on injured reserve. In 2012, Mannelly broke the record for most seasons with the Bears with 15. On December 24, 2012, Mannelly signed a one-year deal with the Bears.
Mannelly retired on June 20, 2014 after a 16-year career. Mannelly ended his career with 81 special teams tackles, the third most by a Bear since 1995 (when the statistic was first officially recorded), and the longest tenured player in team history.
On September 2, 2014, Mannelly debuted with Chicago sports talk radio station 670 The Score as a co-host to Matt Spiegel. Less than a year later, Mannelly left the show citing a lack of interest in covering sports besides football. He will remain on the station as a football analyst.
In 2019, Mannelly partnered with NFL agent Kevin Gold and trainer Chris Rubio to create the Patrick Mannelly Award, given to the best long snapper in college football.