Butt, 26, is a former fifth-round of the Broncos back in 2017 out of Michigan. He signed a four-year, $2.7 million rookie contract that included a $300,948 signing bonus.
Denver declined to tender him a contract this offseason, making him an unrestricted free agent. The Bears signed him to a contract this summer before placing him on the retired list.
In 2020, Butt appeared in five games for the Broncos and caught two passes for five yards and no touchdowns.