Scott Wiese had told friends that if his beloved team didn't win the Super Bowl, he'd take the name of the Indianapolis Colts quarterback.
He even signed a petition in front of 200 people last week at Decatur's Katz Piano Bar saying that he'd do it.
After the Colts defeated the Bears 29-to-17 on Sunday, Wiese started the process.
"A bunch of friends and I were talking one night before the game, and there was a little alcohol involved," Wiese told the Herald-Review newspaper. "I made the bet, and now I've got to keep it. I chose Manning because, well, he is kind of the face of the Colts franchise."
The 26-year-old Forsyth, Illinois, man trudged to the Macon County Courts Facility yesterday and filed the paperwork. The change still has to be approved by a judge.
Wiese says he really cares about the team and that his sacrifice represents the true passion of Bears fans.
Of course, Wiese will never be mistaken for the multimillionaire 6-foot-5-inch, 230-pound Super Bowl MVP quarterback. At 5-feet-11-inches, Wiese, who works at a local Staples store, admitted to the newspaper that his 190-pound body is "not muscle."
He remains unsure how long he will keep Manning's name, and was asked if it will take a Bears Super Bowl win — Chicago last won the big game in 1986 — to reverse the name change. "I mean, well, it may be another 21 years," he told the newspaper.