The Tennessee Titans made the most bizarre head coaching hire of the last decade for one reason: Fear.

When the team elected to remove the interim tag from Mike Mularkey, who took over on a trial basis after Ken Whisenhunt was fired early in the 2015 season, the Titans made it very clear it was because they believe Mularkey's scheme can protect Marcus Mariota.

After investing the second overall pick on Mariota and watching him get battered as a rookie and play with an MCL injury, the Titans worried that allowing Mariota to continue taking big hits could cause him to become gun-shy - or worse.

Mularkey seemed to offer a solution. Indeed, Mariota received better (not good, but better) protection from his offensive line once Whisenhunt was fired after a 1-6 start and Mularkey took over. It didn't help the team's overall fortunes much, though, as the Titans skidded to a last-place finish.

After the season, the Titans sent general manager Ruston Webster packing and replaced him with Jon Robinson. Then, ownership immediately tied Robinson's hands by forcing him to retain Mularkey rather than consider hiring a more deserving head coaching candidate (like, say, Hue Jackson or Josh McDaniels).

Protecting Mariota will be priority No. 1, the Titans stated all offseason, and they proved it by selecting offensive lineman Jack Conklin with their first-round pick and investing heavily in running backs to help force defenses to pull back their pass rush.

Three weeks into the season, the Titans' new-look offensive line is markedly improved over the 2015 version. Conklin has been excellent at right tackle, Taylor Lewan very good on the left side (minus the occasional boneheaded penalty), and free-agent acquisition Ben Jones a boon on the interior.

The Titans' rushing attack is much better, too. DeMarco Murray looks more like the elite 2014 version of himself than the 2015 disaster, and rookie Derrick Henry has shown flashes of superstar ability.

So why, then, is Mariota playing so poorly?

Despite better protection, Mariota's passer rating has dipped from 91.5 in 2015 to 79.3. His yards per completion has dropped from 12.3 to 10.8 and he's already thrown four interceptions after 10 all season as a rookie.

In seeking to maximize Mariota's protection and take pressure off him as a passer, the Titans may have inadvertently stunted his growth.

This should surprise nobody, but it takes more than an effective protection scheme to make a good head coach. All the elements that combined to result in Mularkey's 19-41 record as head coach (one of the worst win rates in NFL history) are still there. Mularkey lacks creativity, and he's stubborn, slow to adjust on the fly, and a step or two behind almost every offensive trend.

Mularkey is failing Mariota as a coach. The former Heisman Trophy winner shouldn't be minimized in the offense, he should be featured. He shouldn't be shielded and coddled, he should be unleashed. Instead of investing in offensive linemen and running backs, the Titans should have invested in receiving weapons.

And they should have invested in a head coach with innovative ideas.

The only time the Titans' offense has looked good this season is when the team is trailing late and must go into hurry-up mode. Then, in flashes, Mariota comes to life and looks like the dynamic player he was at Oregon and often as a rookie.

But Mularkey doesn't want to play fast. He wants to play slow, smash mouth football; a brand of football that no longer works.

Mariota is trying to execute the plan, but it's not in his DNA to play slow and deliberate football. He's a Lamborghini with a boot on his tire.

The longer the Titans continue down this dead-end path, the less chance there is that Mariota will ever figure out how to reverse out of it.