There is no doubt that going into his fifth NFL season Marcus Mariota has never had a backup quarterback with the credentials that Ryan Tannehill brings to the table.

While Tannehill has a mediocre 42-46 record as a starter in six actual seasons with the Miami Dolphins (Tannehill missed all of 2017 with a knee injury), he represents a major upgrade over any backup Marcus Mariota has had behind him in his first four seasons.

Tannehill has a 62.8 career completion percentage with 123 touchdowns and 75 interceptions.

At age 31, Tannehill, who is entering the final year of his contract, would seemingly have a lot of life left in his arm and could potentially parlay this year’s situation with the Titans into a starting role somewhere in 2020.

By comparison, all of Mariota’s previous backups were just that – backups and mainly guys who are hanging on by a thread either due to age or lack of success.

Matt Cassel, who backed up Mariota in 2016-17 has only a 58.8 career completion percentage with 108 TDs and 82 interceptions. Blaine Gabbert, who was the No. 2 QB last year in Tennessee and now is in Tampa Bay, has fared much worse than the other two over his nine-year career, having only a 56.2 completion percentage with 48 touchdowns to 47 picks and only 13 career wins as a starter.

And, for those who recall Mariota’s backup his rookie year, it was poor old Zach Mettenberger, who, while he didn’t have a lot of pieces to work with, never won a game in 10 NFL starts. The Mett Show hit on 60.8 % of his passes with 12 touchdowns to 14 interceptions.