Yahoo Sports is previewing all 32 teams as we get ready for the NFL season, counting down the teams one per weekday in reverse order of our initial 2018 power rankings. No. 1 will be revealed on Aug. 1, the day before the Hall of Fame Game kicks off the preseason.

Even if you didn’t love Marcus Mariota after his first two seasons, you didn’t see an enormous drop coming last year. Nobody did.

Mariota’s 2017 season was strange. He was fine as a rookie, better as a sophomore, and bad in his third season:

2015: 12 games, 2,818 yards, 19 TDs, 10 INTs, 91.5 passer rating
2016: 15 games, 3,426 yards, 26 TDs, 9 INTs, 95.5 passer rating
2017: 15 games, 3,232 yards, 13 TDs, 15 INTs, 79.3 passer rating

Huh? Quarterbacks with Mariota’s resume through two seasons and his draft pedigree rarely collapse at age 24. His 2017 season made no sense.

[Yahoo Fantasy Football leagues are open: Sign up now for free]

Mariota had a hamstring injury that he played through, and while he gets points for toughness, maybe that was the reason he struggled. Or perhaps it was a coaching staff that did OK two years ago and then was overmatched for most of 2017. An injury to Corey Davis, the fifth pick of last year’s draft, didn’t help Mariota. Neither did a step back for the run game, as the coaching staff couldn’t figure out it should play Derrick Henry over a gassed DeMarco Murray.

Mariota will rebound. What he did in 2015, coming from a spread offense at Oregon but looking comfortable in a pro offense as a rookie, was remarkable. His progression in 2016 was fine, though his ability to stay healthy was becoming a concern. Then last season it fell apart with a lack of accuracy, bad decisions and him generally looking tentative and uncomfortable. Without a question it was worrisome.

That leads to an enormous 2018 for Mariota and the Titans. Mariota’s rookie deal expires after the 2019 season. It’s hard to imagine the Titans won’t sign him to a massive extension because teams don’t give up on quarterbacks unless they’re horrendous.. But what if Mariota repeats last season?

Even stranger than Mariota’s significant step back was that the Titans did well in spite of it. The Titans, despite their quarterback being in the bottom half of the league, made the playoffs. Some of that was fueled by a friendly schedule. But they made it, and beat the Kansas City Chiefs in the wild-card round. The Titans weren’t a great playoff team – the Los Angeles Chargers were better over the last three months – but they were one of seven NFL teams to win a playoff game last season.

The coaching change should help Mariota and the Titans. It looked like the underwhelming Mike Mularkey would be retained, because NFL teams rarely fire coaches after playoff seasons even if it’s the right thing to do. Controlling owner Amy Adams Strunk even put out a statement saying Mularkey “is our head coach and will be our head coach moving forward.” Reports said he and the Titans were working on an extension. Then something changed – a disconnect over Mularkey’s comments about being satisfied with Mariota’s development seemed to play a role – and Mularkey was out.

The whole episode was weird, but ultimately the Titans came to the right conclusion. Wasting another year with Mularkey, just because the Titans backed into the playoffs and pulled off an upset, would have been a mistake.

The Titans’ replacement comes with some risk. Mike Vrabel is 42 years old and not that far removed from his playing days with the New England Patriots. In his seven seasons since retiring, he spent three seasons as a position coach at Ohio State, three seasons as a linebackers coach with the Houston Texans and one season as Houston’s defensive coordinator. The Texans gave up the most points in the NFL last season with Vrabel running the defense. That’s due to injuries and a putrid offense without Deshaun Watson, but Vrabel’s coaching resume is still fairly thin. It’s a gamble on Vrabel’s ability to relate to players and that the lessons learned playing for Bill Belichick will rub off (that hasn’t worked with Belichick’s assistants, however).

Vrabel’s coordinator hires were good. Former Baltimore Ravens defensive coordinator Dean Pees “retired” for about a half of a minute, then said Vrabel lured him back after he found retirement wasn’t all he hoped. He’s a good defensive mind. The Titans got Matt LaFleur from the Los Angeles Rams to run the offense. Before spending last season as the Rams’ offensive coordinator, LaFleur was the quarterbacks coach under then-Atlanta Falcons offensive coordinator Kyle Shanahan. LaFleur is the type of young, creative thinker most teams (but not all teams) want.

Vrabel, LaFleur and the rest of the staff will only succeed if Mariota does. Mularkey is gone, at least in part, because of Mariota’s struggles last season. How Mariota plays in his fourth season is by far the most important issue the franchise faces this season. And after Mariota’s strange downturn in 2017, we have no idea what to expect.

Mike Vrabel and GM Jon Robinson, who both come from Patriots roots, spent big on a couple of former New England players. They signed cornerback Malcolm Butler and running back Dion Lewis. Lewis is a talented back, though I was hopeful the Titans would finally trust Derrick Henry in a featured role. I still have no idea what to make of Butler’s Super Bowl benching, but assume he’ll be fine in Tennessee. The Titans made up for losing linebacker Avery Williamson to the Jets by drafting Alabama linebacker Rashaan Evans. Second-round pick Harold Landry has some medical concerns, but he was considered a top edge rushing prospect. Those were the Titans’ only two top-150 picks, but they made them count.

GRADE: B

I was very optimistic about the Titans last season, and many of the reasons are still in place (with, presumably, a better coaching staff). There’s a lot of talent on offense. Not many teams have a running back duo as good as Derrick Henry and Dion Lewis. The offensive line should be good again, assuming tackle Jack Conklin has a quick recovery from a torn ACL suffered in the playoffs. Corey Davis has supreme talent, Rishard Matthews is underrated, Taywan Taylor is an exciting slot receiver and Delanie Walker is still one of the best tight ends in the game. Just because new offensive coordinator Matt LaFleur was with Sean McVay last season doesn’t mean we should assume a Rams-esque explosion this season, but LaFleur has a lot of pieces to work with.

There’s a difference between a player who is injury prone and one who has been unlucky with injuries a couple times. After Mariota missed time due to injuries for a third straight season, it’s worth wondering if he has true durability concerns. He missed four games his rookie year due to a knee injury. His second season ended in Tennessee’s second-to-last game when he fractured his fibula. Last season, a hamstring injury knocked him out of one game and he dealt with an ankle issue too. Then in a playoff loss at New England he suffered a strained quad, which affected the Titans’ play-calling. If Mariota gets injured and misses time again this season, we’ll have to start assuming he will have injury issues throughout his career.

Marcus Mariota focused on his footwork this offseason. He said he wants to work from a wider base, and that could help his pocket accuracy bounce back after it suddenly dipped last season.

Better play-calling would help too. The hope is that the Titans feature more play-action passing, because according to Pro Football Focus Mariota had the highest passer rating and yards per attempt on play action. They’re set up well for it. The Titans have a good running game base with Derrick Henry and Dion Lewis, and new offensive coordinator Matt LaFleur seems to understand how to use Mariota’s strengths. LaFleur said his focus will be on generating explosive plays, and it’s a good bet that many of Mariota’s shots downfield will come off play action.

“There’s always going to be a foundation, and the foundation really starts with our running game and how we tie the pass game to our running game,” LaFleur told the team’s official site. “We want to keep the defense off-balance, you have to keep them guessing. If you have plays that start out looking the same that are different, it keeps the defense guessing.”

The Titans’ passing offense wasn’t great last season, and it’s fair to wonder how much Corey Davis’ hamstring injury and subsequent rookie struggles were a factor. The team drafted Davis fifth overall and he looked like a good bet to lead the team in receiving, even as a rookie. Then he suffered a hamstring injury early in training camp and that affected him deep into the season. It’s hard enough to produce as a rookie, and it gets even more difficult when you miss most of camp and the preseason. Davis showed in a two-touchdown playoff game at New England that he can be well worth that high pick. There’s no real reason to believe Davis can’t be a true No. 1 receiver for many years to come.

“I just want to be better than last year, which shouldn’t be that hard,” Davis said, according to the Titans’ site. “Just stay healthy, get open when you’re out there and catch the ball, and block when you need to.”

From Yahoo’s Andy Behrens: “If you’re a fantasy owner who still feels burned and betrayed by Marcus Mariota, we get it. Completely understandable. It was rarely a clinic, as he averaged just 215.5 yards per game and tossed a career-worst 15 interceptions. But we’re asking you to give Mariota just one more chance, now that he’s paired with a coordinator who seems legitimately interested in maximizing his strengths. Tennessee OC Matt LaFleur has spent the past three seasons working under Kyle Shanahan (2015-16) and Sean McVay (2017), two of the NFL’s most inventive play-callers. The last two quarterbacks coached by LaFleur both led the league in yards per completion (Matt Ryan at 13.3, Jared Goff at 12.9). The last two teams he was associated with led the league in scoring.

“So yeah, there’s reason to be optimistic about the changes to the Titans offense. LaFleur has been candid about the need to tailor a system to his talent, and the need to generate more explosive, field-flipping plays. This team’s roster has plenty of playmakers. Let’s just see what Mariota can do with a new playbook and excellent weapons. He’s a well-priced option (Yahoo ADP 124.3) for those who draft their QBs late.”

[Booms/Busts: Fantasy outlook on the Titans.]

[Yahoo Fantasy Football leagues are open: Sign up now for free]

Fumble luck is a big factor for an NFL team, and almost entirely out of its control. Since turnovers often determine a game, it’s clearly important. The Titans had the worst fumble luck in the NFL last season, recovering a league-low 34.3 percent of fumbles last season according to Team Rankings. If you assume a team should recover about 50 percent of fumbles, the Titans should be in for better fortune this season.

HOW WILL THE COACHES SPLIT TIME BETWEEN DERRICK HENRY AND DION LEWIS?

Years from now I’ll wake up in a cold sweat, remembering the 2017 Titans coaching staff staring blankly at the field as DeMarco Murray plodded along, with a fresh Henry waiting on the sideline. Make no mistake, had Murray been healthy for that playoff game at Kansas City, the coaches would have given him like 18 carries, he’d have had about 53 yards and the Titans would have lost. Instead, Murray was hurt and the staff had to play Henry, who rushed for 156 yards and a touchdown in a win. A good example of how Mike Mularkey was in over his head was his insistence on playing Murray over Henry.

Anyway, Murray is gone and that seemed to open up a full-time role for Henry. But the Titans gave Lewis a four-year, $19.8 million deal, the 12th highest deal by average for an NFL running back. That’s not backup money. Lewis earned the contract. He ranked first and second among all NFL running backs last season in Football Outsiders’ two main metrics for backs, DYAR and DVOA.

Depth is great and it doesn’t hurt to have two talented backs, especially since their skill sets complement each other well. This seems like a clear 50-50 split on snaps, and we’ll wait again to see what Henry might do with a full workload.

The Jacksonville Jaguars, not the Titans, ended up being the AFC South’s breakout team last season. It’s also worth mentioning the Titans swept the Jaguars, and at this time last year there were a lot of reasons to believe Tennessee was on the verge of something big. If a poor coaching staff held back a talented roster, maybe their breakout comes this season. It’s not like they have far to go after making the playoffs last season.

If Marcus Mariota struggles with a new staff, the Titans go into that frightening zone in which they probably have to pay their quarterback an enormous extension but wonder if he’ll ever be worth it. We also have no idea if the unproven Mike Vrabel is a good head coach. I don’t have a ton of questions about the roster as a whole, but having questions about the quarterback and coach is more than enough to cause concern.

The Titans got into the playoffs by squeaking by some bad teams last season, but the good news is the schedule is pretty soft again. I assume the coaching staff will be a big improvement and Marcus Mariota will get back on the path he was on his first two seasons. I don’t anticipate the Titans pass the Jaguars, but they’ll be in the mix for a wild card spot. With a break or two, some improvement (and health) from Mariota and a good rookie season from Mike Vrabel, they could make it right back to the playoffs.

32. Cleveland Browns
31. Indianapolis Colts
30. New York Jets
29. Arizona Cardinals
28. Buffalo Bills
27. Cincinnati Bengals
26. Chicago Bears
25. New York Giants
24. Miami Dolphins
23. Washington Redskins
22. Tampa Bay Buccaneers
21. Houston Texans
20. Seattle Seahawks
19. Oakland Raiders
18. Denver Broncos
17. San Francisco 49ers
16. Detroit Lions

– – – – – – –

Frank Schwab is a writer for Yahoo Sports. Have a tip? Email him at shutdown.corner@yahoo.com or follow him on Twitter!
Follow @YahooSchwab