Tennessee will acquire Tannehill and a 2019 sixth-round pick in exchange for a 2020 fourth-round pick and a 2019 seventh-rounder, a source told ESPN's Adam Schefter.
The quarterback will also receive a new contract as part of the trade. He'll earn $7 million fully guaranteed on the one-year pact, according to Schefter, and has a chance to earn over $5 million more in incentives. Miami will also pay $5 million of Tannehill's fully guaranteed money in the form of a signing bonus.
He's expected to be Marcus Mariota's backup this upcoming season.
The Titans also released Blaine Gabbert on Friday, general manager Jon Robinson announced, according to ESPN's Turron Davenport. Gabbert served as Tennessee's backup last season and started three games in relief of an injured Mariota.
The trade wraps an up-and-down tenure in Miami that began with high expectations. Tannehill never eclipsed his 27 passing touchdowns thrown in 2014 and failed to take the next step as a franchise pivot. He's also missed 24 games over the last three seasons with various injuries.
Tannehill was the Dolphins' first-round pick (No. 8 overall) in 2012. He's been the team's starting pivot for six seasons, missing the 2017 campaign with a torn ACL.