For Maryland football's secondary, it's all about preventing – and creating – the big play

Maryland football's 2015 lineup is riddled with uncertainty. When Richmond visits Byrd Stadium to open the season on Sept. 5, the Terrapins could plausibly start different players at quarterback, running back, tight end, receiver, linebacker, punter and on both sides of the line. On Maryland's entire roster, just two areas feel completely locked in. One is kicker, where the Terps return Lou Groza Award winner Brad Craddock. The other is the secondary, where Maryland has to find stability in an otherwise young and evolving defense.

Maryland's defensive backfield will include three three-year starters and another who's been in and out of the team's lineup for almost half a decade. All are talented, and all are experienced. On their own merits, they'll be good. But will they be stingy enough to reliably back a brand-new 4-3 front packed almost completely with first-time starters?

That's the challenge for 2014 All-Big Ten (and 2015 preseason All-American?) cornerback Will Likely and his friends. At cornerback, Maryland will pair the diminutive but explosive Likely with converted safety Sean Davis. Between and behind them will be safeties Anthony Nixon and A.J. Hendy. Others will rotate in for nickel (five-defensive back) and dime (six) formations, but that's Maryland's nucleus. Here's the whole secondary:

(Hat tip to SB Nation's Bill Connelly for a neatly constructed organization.)

Maryland only loses cornerback Johnson (graduation) and depth safety Dancel (transfer). As a statistical proportion of Maryland's defense last year, those two weren't much. Johnson dealt with injury and only started seven games, and Dancel got his only start while Johnson and Hill were both down.

The core of the defensive backfield is entirely intact, and the starters are hugely talented. The average 247Sports Composite rating of Maryland's four secondary starters this season is 0.8729. That's decimal points below a four-star average and equivalent to being about the 40th-best cornerback in a given class, only now these players all have years of experience. Likely, a former Gatorade player of the year in Florida, is the sort of player Maryland never would've gotten if he weren't 5'7. Davis and Hendy were important local gets, and Nixon (from the greatest city in the world) was a three-star forced into immediate action by roster shortage as a freshman. There's an awful lot of upside here.

Preventing the big play

The Terrapins were pretty good at generating quarterback pressure last season. They finished 33rd nationally in adjusted sack rate, a figure that jumped to 28th on passing downs, when secondaries are most targeted. Their 2.4 sacks per game ranked 44th.

The secondary held up its end of the bargain, too: the Terps ranked 44th in defensive passing S&P despite a porous run defense that left them often thin in the secondary. More traditional metrics write the same, stout story: Their 6.7 yards allowed per passing attempt were 38th out of 128 teams. Their 121.01 passer rating-against was 40th, their 55.5 completion percentage allowed 34th. They were good at these things.

But last year's iteration of Maryland's pass defense felt frustrating, somehow. When Likely wasn't intercepting passes (which he did six times), the Terps were busy being gashed for chunk gains from scrimmage. They gave up 114 completions of 10 yards or more. Of those, 44 went for 20-plus, 20 for 30-plus and 11 for 40-plus. Those were all bottom-four figures in the Big Ten and notably worse than the national medians.

The Terps gave up 253 completions, and 45 percent of them went for more than 10 yards. Seventeen percent were longer than 20. That is a lot. The best passing defense in FBS (Clemson) let just 13 percent of opposing receivers have more than 20 yards. The worst passing defense (SMU) was at 19 percent, more in Maryland's neighborhood. By national average, Maryland was "meh" in the big play department. But if we localize things a bit, just to the Big Ten, it's easy to see how badly Maryland got gashed sometimes. Look at the raw totals:

On everything within 59 yards of the line of scrimmage, each 10-yard interval treated Maryland badly compared to the rest of its league (this is a counting stat, which I normally don't love, but it illustrates the blunt on-field cost of Maryland's repeated permissiveness of big plays.). Note that Maryland's overall pass defense was impressive overall (fifth in the league in passing S&P+), despite a bad run defense that rendered it frequently exposed. The defense's inability to prevent chunk passing plays sticks out badly in this context, especially given Maryland's mostly strong quarterback-pressuring.

On everything within 59 yards of the line of scrimmage, each 10-yard interval treated Maryland badly compared to the rest of its league (this is a counting stat, which I normally don't love, but it illustrates the blunt on-field cost of Maryland's repeated permissiveness of big plays.). Note that Maryland's overall pass defense was impressive overall (fifth in the league in passing S&P+), despite a bad run defense that rendered it frequently exposed. The defense's inability to prevent chunk passing plays sticks out badly in this context, especially given Maryland's mostly strong quarterback-pressuring.

It actually makes a bit of sense that Maryland would struggle in this regard. Likely is a thrilling talent, but he's also the shortest player on the field, which makes him vulnerable in the vertical passing game against big receivers. Maryland's cornerbacks behind him were either inexperienced or hurt for most of the season. Of last year's group, only Davis and Likely have what would be considered top-end athleticism to snatch balls over the top of the formation, so Hendy's return from suspension as a fifth-year senior should be helpful. Even though Maryland doesn't label its safeties as "strong" or "free," Hendy will probably play a bit deeper to handle long passes, and Nixon will play closer to the defensive box.

Creating turnovers

How well Maryland will prevent the big play is an open question. But the Terrapins should feel optimistic about their secondary's ability to create the big play  – that is, to intercept passes thrown by opposing quarterbacks. This prediction comes on the heels of a really weird season for Maryland, one in which the Terps were second in the Big Ten in passes defended (i.e., broken up or picked off), with 68, but fifth from last in actual interceptions with 9.

That's a pretty odd contradiction. Ohio State's bars make sense, as teams defending the most passes should be stealing the highest number of them away from the other team. The Buckeyes were the best at both. Maryland was good at one, not the other. Is there anything substantive behind that, or is it just dumb luck?

Research by our SB Nation colleague Connelly has found that a defense can expect to post an interceptions-to-passes defended ratio of about 21 or 23 percent – meaning it should get one interception for every five attempts it breaks up (including interceptions themselves). In this sense, Maryland was brutally unlucky last season:

The Big Ten's average was virtually exactly what it's supposed to be – about one interception for every five passes defended, for a ratio of 0.21. Maryland's 0.13 interception-to-passes defended ratio was the lowest in the league. This isn't much, if anything, more than random variation, and it crushed the Terps. The prior three years, their ratios had been all over: 0.26 in 2013, a wildly low 0.08 in 2012 and 0.27 in 2011.  Had Maryland's 2015 ratio been the Big Ten average of 0.21, it would've meant a full 14 interceptions over the 68 passes it defended in 2014 – or five additional interceptions. That's enough to flip the result of one game, certainly, and possibly more than that.

Notice, too, how there are great defenses on both sides of the league average. Ohio State's at the top, which makes sense given the Buckeyes' defensive playmakers, but strong defenses like Wisconsin and Michigan are at the bottom.

There's no reason to think Maryland's secondary is full of players with especially poor hands, so there's no reason to think the team's ratio won't normalize this season. If that happens, it'll mean more turnovers. If that happens, Maryland's defensive backs could be one of the better groups in the sport.