"The time has come to move on from playing the game of football," Miller wrote on Instagram. "It has been an incredible journey for myself and my entire family and we can't thank you enough for your continued support. I would love nothing more than to step onto Soldier Field one last time, but physically I cannot give the game and our fans what they deserve. It's difficult to find the words to express my love and gratitude to every single person that has cheered my name, lifted me up and stood strong with me throughout my career. I am forever grateful."
The tight end dislocated his left knee and tore his popliteal artery on Oct. 29, 2017, against the New Orleans Saints. He underwent numerous surgeries and was at risk of amputation, though doctors managed to save his leg.
Miller played for the Bears from 2014 to 2017. He was with the Jacksonville Jaguars from 2009 until 2012 and spent an offseason with the Tampa Bay Buccaneers in 2013.
The 34-year-old established career highs in receptions (47) and receiving yards (486) in 2016 with Chicago. He maxed out at five touchdowns in 2015.