Chicago waived Brandon Hartson on Sunday, so they are in need of a long-snapper before the season gets underway for them this weekend.
Patrick Mannelly, who had been with the Bears for several, years retired back in June.
Cain, 34, actually signed with the Bears as an undrafted free agent out of Massachusetts back in 2004. He spent four years with the Jacksonville Jaguars before rejoining the Bears for two games in 2013.
The Tampa Bay Buccaneers signed him to a contract this past March, but he was released a week ago.