Jenkins has played primarily on the outside and now figures to start alongside second-year cornerback Kristian Fulton. Jenkins brings veteran leadership to what was otherwise a young group of cornerbacks.
Jackson's fifth-year option salary of $10.244 million for the 2021 season was set to become fully guaranteed on Wednesday at 4 p.m. ET when the new league year begins.
The Titans create $3,416,666 in salary-cap space by releasing Kelly. His release also results in $3,166,667 in dead money on their cap.
The New Orleans Saints released Jenkins earlier this month to clear much-needed space as they scrambled to get under the salary cap.
He started 15 games in New Orleans last season, including the playoffs, after the Saints claimed him off waivers from the New York Giants late in the 2019 season.
The 5-foot-10, 190-pounder had three interceptions last season, one of which he returned for a touchdown in a Week 1 victory over Tom Brady and the Tampa Bay Buccaneers. He had 12 passes defensed last season and has a total of 118 in his career.
Jenkins, 32, went to the Pro Bowl with the Giants in 2016 and has 26 interceptions in his nine-year career with the Rams, Giants and Saints.
A second-round draft pick with the Rams in 2012, Jenkins has started 125 regular-season games and four more in the playoffs.
Kelly signed a three-year, $21 million deal exactly a year ago, then started all 16 games at right tackle. Tennessee acquired him in a trade with Philadelphia in 2016, and Kelly played in 74 games over the past five seasons.
The Titans picked up the fifth-year option on Jackson, the 18th overall pick in 2017, last year as well.
Jackson started 41 of 46 games for the Titans but a knee injury just before the start of the season limited him to three games in 2020.
Tennessee drafted an offensive tackle at No. 29 overall last April, but Isaiah Wilson wound up playing only four snaps before the Titans agreed to trade him to the Miami Dolphins this offseason. The Titans also agreed to terms with offensive tackle Kendall Lamm on a deal Monday.
ESPN's Turron Davenport, Mike Triplett and The Associated Press contributed to this report.