The deal, which has an average annual value of $29.5 million, includes $62 million fully guaranteed, the source told Darlington. Tannehill also will receive $91 million in total guarantees, according to Darlington. The Titans announced a multiyear extension for Tannehill on Sunday but did not disclose terms.
Tannehill took to Twitter shortly before the Titans' official announcement, saying "lets run it back."
The reported agreement came after sources told ESPN's Dianna Russini earlier Sunday that Tennessee was not interested in Tom Brady and was instead focusing on a deal with Tannehill. Tennessee was widely speculated as a potential free-agent destination for Brady, given the Titans' impressive postseason run and Brady's friendship with Titans coach Mike Vrabel.
Sunday's agreement keeps Tannehill from becoming a free agent and means he will be Tennessee's signal-caller for the foreseeable future.
Tannehill and the Titans eliminated Brady and the Patriots from the postseason in the AFC's wild-card round and upset the top-seeded Baltimore Ravens in the divisional round before losing to the Kansas City Chiefs in the AFC Championship Game. Tannehill threw five touchdown passes and ran for a score while committing just two turnovers in Tennessee's three postseason games.
Tannehill was named the NFL Comeback Player of the Year for 2019 after he finished last season with an NFL-high 117.5 passer rating while throwing for 2,742 yards, 22 touchdowns and six interceptions in 12 games. He completed 70.3% of his passes and averaged 9.6 yards per completion.
The No. 8 pick by the Miami Dolphins in the 2012 draft has a 49-49 record as a starter. Tennessee acquired Tannehill and a 2019 sixth-round pick from the Dolphins in exchange for a 2020 fourth-round pick and a seventh-round pick. He was named the starter after coming in to relieve Marcus Mariota in Week 6 against the Denver Broncos.
ESPN's Turron Davenport contributed to this report.