[Editor’s Note: PFN originally ran this story on October 17, 2019. Since then, Ryan Tannehill has led the Tennessee Titans to a 6-1 record while leading the NFL in completion percentage (72.7%) and yards per attempt (9.89), compiling a passer rating of 121.7 in the process since Week 7.]
According to ESPN’s Ian Rapoport, the Tennessee Titans have named Ryan Tannehill the starter for Week 7 against the Los Angeles Chargers. Former Heisman Trophy-winning QB Marcus Mariota will be benched for the first time in his career.
After an embarrassing shutout in Week 6 against the Denver Broncos and a putrid performance by Mariota, many may be quick to abandon him. But that may be a knee-jerk reaction.
While he did earn the worst grade of the entire season according to PFN’s Offensive Share Metric (OSM), there is plenty of reason to see this as an outlying performance. However, things are looking rough as the offense has struggled in half of their games so far this season.
Tennessee Titans swap quarterbacks mid-game
It was a rough day in Denver. Mariota failed to gain more than 100 passing yards and completed just 7 of his 18 pass attempts with a measly 3.5 yards per completion. The Titans as a whole were able to break 200 total yards of offense on the day with 204, but it was clear that head coach Mike Vrabel needed to give his team a spark.
Insert former Miami Dolphins starting QB Ryan Tannehill. After Mariota’s second interception with 8:06 left in the 3rd quarter, Vrabel benched Mariota for the seven-year starter the Titans acquired in a trade this past offseason. Tannehill played better, but the team still failed to score despite reaching the redzone twice.
So if the team still didn’t score, did the QB change do anything for the Tennessee Titans offense? Tannehill generated some momentum and earned an OSM grade of 36.97, making him the fifth-best QB in Week 6. What did the two QBs do so differently?
For starters, let’s look at the depth of their pass attempts. Both Mariota and Tannehill had nearly identical intended air yards averages at 9.6 and 9.7, respectively. The difference comes from the completed passes. Mariota averaged 4.2 completed air yards while Tannehill averaged 8.5 CAY, the third-best in Week 6. The air yards differential brings the story together, as Mariota had a differential of -5.4, the worst of Week 6. Meanwhile, Tannehill had an average air yards differential of -1.2, the lowest AYD of QBs with an intended air yards average of 9 or higher.
What does this mean? The intended air yards average is how far a quarterback intends to throw on all of his pass attempts. So both Mariota and Tannehill were attempting passes of the same distance. The completed air yards average is the average distance through the air of all a quarterback’s completions. While Mariota was trying longer passes, on average, he was unable to complete those against the Broncos and settled for shorter completions. Tannehill was completing passes on average over 4 yards deeper than Mariota.
Next, I examined the difference in completion percentage. Tannehill went 13 for 16 in his quarter and a half, completing 81.3% of his on the day. Not much else needs to be said about the 42% difference between Tannehill’s and Mariota’s completion percentage. One guy could not get anything going, and the other came in and performed well. In the situation of the game, it was a great coaching decision to help the Tennessee Titans build some momentum. Long term, however, that’s a different story.
The long-term QB picture
The Titans are in a rough spot right now. Sitting at 2-4 on the season, a change had to be made to a team that seems to be under-performing. While Tannehill did provide a spark this past Sunday, the team still failed to generate a comeback, and the overall OSM grades point to Mariota being the better QB.
OSM utilizes the NFL’s Next Gen Stats to formulate scores since it began in 2016. Therefore, PFN is only able to generate OSM scores for the previous three seasons. However, in both 2016 and 2018, Marcus Mariota earned higher OSM grades than Ryan Tannehill. Tannehill was sidelined with a torn ACL for the 2017 campaign, but many consider the 2016 season to be one of his best performances. Even in that season, though, Mariota’s OSM grade of 31.29 was still better than Tannehill’s 29.68.
It is not a huge difference, but it’s there. And in 2018, Mariota would be ranked at QB 21 for overall quarterback OSM grades, while Tannehill graded as the 32nd QB out of 39. The offense has struggled, but Mariota has improved on his tendency of turning the ball over this season. His two interceptions in Week 6, against arguably one of the best passing defenses they will face all season, were his first of the season. His OSM for the season also points to his abysmal performance being an outlier.
In Weeks 1 and 2, Mariota earned an OSM grade of 15. He would then improve his grade to a 29.87 in Week 3. He followed that up with his best performance of the season in Week 4 with an OSM of 32.08. Mariota returned to earth a bit with an 18.95 in Week 5 and, as discussed earlier, had the worst performance of any quarterback this season with a -1.79 during Week 6. There’s a bit of a curve, but his overall grade is currently at 20.47.
If the Titans had a rookie waiting in the wings, the move to bench Mariota would make much more sense. However, with Tannehill being the usurper, it’s hard to imagine him having a more profound effect on the Titans offense – especially when Mariota has had a higher OSM grade in the past two seasons in which both have played.
With Tannehill getting the nod for Week 7, some intriguing questions come to mind. Has Mariota’s time with the Titans come to an end? How short of a leash does Tannehill have? At what point does Tennessee return to Mariota if Tannehill’s performance goes south? All this and more remains to be seen in the weeks to come, and the answers to these questions will have long-term ramifications for the Titans.