Milligan is getting a promotion from the practice squad in order to provide Indianapolis with more depth at safety in the wake of Mike Mitchell's (calf) placement on injured reserve. However, the third-year Toledo product is unlikely to see enough playing time to be worthy of IDP consideration.
Milligan was waived by the Colts on Friday.
Milligan was promoted from the Colts' practice squad to the active roster last Saturday and was not active for last week's win over the Giants. The 24-year-old will likely have to wait until 2019 to try and make his NFL debut, with the regular season finishing up Sunday.
The Colts promoted Milligan to the 53-man roster Saturday.
Milligan didn't secure a 53-man spot out of the preseason, but he will provide some depth in the secondary with a number safeties injured for the contest. Should he take the field Sunday, it would mark the first time in his career he's appeared in a game.
Milligan left Thursday's game against the Browns with a chest injury and will not return, Justin Rogers of the Detroit News reports.
Milligan is currently sitting as a depth option on the Lions' safety depth chart, and may be on the outside looking in for a roster spot. He will hope the injury is not serious in order to have a chance at making Detroit's 53-man squad.