Chicago hosted Santos for a visit last week, so it was clear that he could be signed to a contract once he passed a physical for the team.
Santos, 25, wound up signing on with the Chiefs as an undrafted free agent out of Tulane back in 2014. He returned to the Chiefs this past March on a one-year restricted deal worth $1.797 million.
Kansas City elected to place him on injured reserve with a groin strain at the start of the season and cut him loose with a settlement soon after.
In 2017, Santos has appeared in three games and converted all three of his field goal attempts along with 12 of 12 extra point tries.