There is no doubt that going into his fifth NFL season that 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 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 104 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 60.3 percent of his passes with 12 touchdowns to 14 interceptions.

– Terry McCormick