The Colts had a need at the position after the release of starting cornerback Pierre Desir last week.
Once viewed as one of the best cornerbacks in the league, Rhodes became a free agent when the Vikings released him March 13. Minnesota released the All-Pro defensive back due to his decreased production and large cap hit.
Rhodes, who had a $12.9 million cap hit and was under contract through 2022, gave the Vikings $8.1 million in savings with his release, according to Spotrac.
Rhodes, 29, was selected in the first round of the 2013 NFL Draft and signed a five-year, $70.1 million extension before the 2017 campaign. The former Florida State product earned three Pro Bowl appearances with the Vikings but struggled over the past two seasons.
In the 2019 season, Rhodes was flagged for 10 penalties, allowed a 127.8 passer rating in coverage and failed to record an interception for the first time since 2013.
Rhodes will add veteran experience to a young Colts secondary that features Kenny Moore, Quincy Wilson, Rock Ya-Sin and Marvell Tell. Moore and Wilson have the most experience in Indianapolis' cornerback group, as they're headed into their fourth NFL season.
Rhodes will become the third defensive player acquired by the Colts this off-season. Indianapolis traded for San Francisco 49ers star defensive tackle DeForest Buckner on March 16 and signed Sheldon Day this week.