Tannehill will serve as the Titans’ backup quarterback to Marcus Mariota this season.
Gabbert, 29, is a former first-round pick of the Jaguars back in 2010. After three years in Jacksonville, he was traded to the 49ers in return for a sixth-round pick back in March of 2014.
Gabbert played out the final year of his two-year, $4 million contract before eventually signing a one-year, $855,000 contract with the Cardinals.
The Titans and Gabbert agreed to a two-year contract worth $4 million last year.
According to OverTheCap.com, releasing Gabbert will free up $1.5 million of available cap space while creating $500,000 of dead money.
In 2018, Gabbert appeared in eight games for the Titans and completed 61 of 101 pass attempts (60.4 percent) to go along with four touchdowns and four interceptions.