Ryan Tannehill's Injury May Help Fantasy Football Owners Who Wanted to Draft His Receivers

I don't know if you heard, but Ryan Tannehill hurt his knee again yesterday.

Again? Yes, again. Because this is the same exact knee he injured last year. Except this time, he may get it surgically repaired.

That means Tannehill could be out for the season. It's not official yet, so that's just speculation, but it's entirely possible given reports.

In turn, the Dolphins are looking at current backup Matt Moore or, potentially, a quarterback not currently on their roster like Jay Cutler or Colin Kaepernick to play under center for them this season.

Since Moore's currently on the roster and probably has the highest chance of starting Week 1 -- you know, because it's August, so a dude coming off the street may have a tough time quickly adjusting -- let's look at how things differ going from Tannehill to Moore from a fantasy perspective.

If they differ at all.

Gase's Impact

You could make a strong argument that Ryan Tannehill had his best season in the NFL last year. And, probably not coincidentally, it was the first year quarterback guru Adam Gase was coaching the Dolphins.

Our Net Expected Points (NEP) metric tells us the number of actual points a player is adding for his team above or below expectation. Rather than getting into the details of the metric here, you can read more about it in our glossary.

Tannehill's Passing NEP per drop back rate in 2016 of 0.09 was the best of his career, and it was on par with what he did in 2014 compared to the league's average rate. One thing to note, though, is his 45.32% Success Rate, or the percentage of passes that gain positive expected points. Despite his higher efficiency, his Success Rate was roughly along the same lines of what he's done throughout his career.

Why? Well, usually when this happens, it's because of big plays. And that lines up to what happened to Tannehill last season.

This certainly puts a little context around the expected point numbers above. A huge reason for Tannehill's efficiency last season was due to a higher air yards per attempt (on completed passes) rate to go along with a career high in yards after the catch per attempt. That higher air yards profile, though, brought some natural variance, hence the lower Success Rate.

Moreover, Tannehill improved his deep ball passing under Gase. Here's a look at some numbers throughout Tanny's career on throws that travelled 15 or more yards through the air:

This, too, explains the values our expected points model produced. Tannehill saw 30.88% of his yards come on 15-plus yard throws, which was a career high. He also had a substantially higher completion percentage on such throws compared to most other seasons, most notably his 2014, where his efficiency was strong and his Success Rate was high. A big reason for that Success Rate number seems to be due to the fact that he was making safe throws.

What we're getting at here is two-fold. First, Tannehill improved under Gase. Whether it was natural career progression or Gase himself, the bottom line is that Tannehill was a slightly better quarterback than we've seen in the past.

Second -- and probably most importantly for fantasy football purposes -- is that Tannehill's deep ball game was substantially better in 2016 than any other season of his career when you factor in his overall efficiency.

Matt Moore's Replaceability

Anytime we're dealing with a backup quarterback, sample size is an issue. That's no different for Matt Moore.

It should be noted, though, that he's more than a competent second-stringer.

Moore has dropped back to pass 100 or more times in a season on four occasions and, last year, he had 88 drop backs (87 attempts). That small of a sample size can skew numbers.

And skew numbers it did. Moore had a 0.33 Passing NEP per drop back during the regular season for the Dolphins, which was actually fourth-best in football among the 48 signal-callers with 50 or more drop backs. That's silly.

It's also not sustainable.

When charting all of these 50-plus drop back quarterbacks and their efficiency (Passing NEP per drop back) versus Success Rate, you can start to see which guys played a little over their heads. One of those players was Moore -- given his 0.33 expected points per drop back rate, we would've expected a Success Rate closer to 52% or 53%. Instead, his Success Rate was 47.73%, which lines up more to a league-average quarterback.

Moore's three starts last season also came against the Jets, Bills, and Patriots. According to our schedule-adjusted numbers, the Jets had the 28th-ranked secondary last year, the Bills were 17th, and the Patriots finished 13th. And against the Jets, he had an absurd 0.93 Passing NEP per drop back average thanks to a 12 for 18, 236-yard, 4-touchdown stat line.

This just piles onto the notion that we really can't fully judge what and who Matt Moore is as a quarterback.

It should be noted, though, that Moore did seem to throw the ball deep more often than Tannehill did.

Again, we're looking at a small sample here and the matchups last season dictated this a bit, but I suppose we can feel optimistic about the deep ball tendency in Gase's offense. Not that they happen frequently, but that they happened independent of who was under center.

Bringing It Together

Here's the boring, maybe-obvious-to-some bottom line with all of this: though Moore has been a good backup, we don't have enough information to say that he's simply a lateral move off of Tannehill. In a small sample, you could argue he's been better than Tanny. But you also have to remember that there's a reason Tannehill is the starter, and there was at least some upside with Tannehill being under center for a second season under Gase.

With that being said -- and this is probably the most important piece of all -- we can't ignore what the Dolphins did last season to enable both Tannehill and Moore to succeed. They became competent running the football, and they were content running the football.

From Weeks 1 through 5 -- which were the pre-Jay Ajayi breakout weeks -- the Dolphins had a 1.89 drop-back-to-run ratio, ranking as the eighth-most pass-friendly team in football.

Post-Ajayi going HAM, that number fell to 1.06, which was only higher than the run-first Cowboys and Bills.

On top of this, they ran at the slowest pace in the NFL last season -- they ran just 913 plays in total, which was 47 fewer than any other team in football.

The Dolphins very clearly want to run the football and play slow.

And that's why this injury may actually help the fantasy owners who were preparing to select Jarvis Landry and DeVante Parker. If Tannehill is indeed out for the season, you'd imagine their average draft positions will slip a bit. That'll actually make their costs more reasonable considering there were already volume concerns in this offense.

But if their costs don't change? It only seems reasonable to pass on the team's pass-catchers.