In 2015, the Giants defense was awful. They finished the season 30th in defensive DVOA. No team gave up more yards (more than 420 per game). Just one team gave up more yards per play (6.1). And only two teams surrendered more points (27.6 per game).

New York GM Jerry Reese saw he had too many holes on his roster, so he looked outside his organization for a fix. He convinced nose tackle Damon Harrison to come over from the Jets on a five-year, $46.3 million deal, he signed former Dolphins defensive end Olivier Vernon to a five-year, $85 million contract, and he inked cornerback Janoris Jenkins to a five-year, $62.5 million deal.

Big-money free agency is frequently a dangerous and unreliable venture — whether it’s because of poor fit, a drop-off in performance, or both — but all three of Reese’s major acquisitions have had Pro Bowl–caliber seasons in their new home. The Giants have emerged as one of the league’s top defensive groups (currently fourth in DVOA), but for as great as the new trio has been, the development of a homegrown player is what’s making it all work.

Landon Collins has rebounded from a disastrous rookie season — when he earned the lowest coverage grade from Pro Football Focus of any safety in the league — and has emerged as the straw that stirs the drink for the Giants defense. Sure, Harrison is an elite run plugger; he’s currently Pro Football Focus’s top-graded interior rush defender. Yes, Vernon has eight sacks and has lived up to his billing as a quarterback’s nightmare. And OK, Jenkins has been an artist in coverage; we just saw him completely shut down Dez Bryant in New York’s upset win over the Cowboys. But Collins has done all three of those things from the safety spot: Through 14 weeks, he leads all safeties in tackles (100), interceptions (five), and passes defensed (13), and is tied for the lead in sacks (3.0). He does it all, and is not only one of the favorites for the Most Improved Player award, but he belongs in the conversation for Defensive Player of the Year.

As a rookie, Collins was too stiff and too slow in coverage. His size also became enough of an issue that Giants defensive coordinator Steve Spagnuolo discussed moving him to linebacker in Year 2. Not wanting to make the position change, he lost 10 pounds over the summer, and his smaller stature has had little effect on his ability to lay the wood. Collins has 14 run stops this year, per Pro Football Focus (ninth among safeties), and he’s shown off his power on a few big-time hits in coverage.

One came in a Week 5 loss to the Packers. Just after the ball arrived for Jordy Nelson on the sideline, Collins came screaming downfield to knock away what should’ve been an easy catch for a big gain.

In last week’s win over the Cowboys, Collins picked up Jason Witten in coverage as the tight end ran a short route toward the sideline. Collins quickly closed and knocked him backward.

Big hits are great, but safeties in the modern pass-happy game must be able to cover. And Collins’s lighter frame has improved his fluidity in coverage. Opposing quarterbacks have found the end zone just twice when targeting Collins on 56 throws, notching a 60.1 passer rating on the season (15th best among safeties, per PFF). Last year, opposing QBs had a 125.7 rating (eighth worst) when targeting him.

The first thing that pops off the tape from Collins’s coverage is how quickly he can recognize route combinations and react to how they develop. Against the Bears in Week 11, Collins had two pass breakups, and on both, he was tasked with a zone coverage in the curl/flat area. In each play, he not only kept an eye on the quarterback, but quickly recognized the routes coming into his part of the zone. Without being able to diagnose the situation and react near-instantaneously, he would have been too late to make either play.

We saw this against the Steelers in Week 13, as well. When Ben Roethlisberger tried to find tight end Ladarius Green on a seam route late in the second quarter, Collins recognized it and broke up the pass.

Collins then did it again early in the third quarter. In the same way some basketball players — John Stockton, Jason Kidd — just have innate floor vision, Collins manages to process the chaos in front of him with ease. With his eyes on Roethlisberger, he still picked up Cobi Hamilton on a crossing route, jumped it, and knocked the ball down.

Sometimes, Collins’s aggression on these plays can be exploited, and the Steelers made him pay later in the third quarter when they ran a double move with Green that lured the Giants safety into jumping what he thought was a short route meant to pick up a first down on third-and-4. Instead, Green juked, then ran deep, burning Collins for a touchdown. But plays like this are few and far between. More often than not, he’s been disciplined in making sure plays don’t get behind him. Plus, his decision-making on when to break on the football has been precise.

He picked off Carson Wentz in Week 9 when the rookie passer overthrew his target …

… and, in Week 10, he jumped a route and picked off Andy Dalton when the Bengals quarterback tried to hit Tyler Kroft up the seam:

Of course, safeties can’t always play in zone with their eyes in the backfield. Certain coverages call for Collins to pick up receivers and tight ends in man coverage, and he’s done this several times this year. Against the Cowboys in Week 1, Collins ran with Dez Bryant on a deep fade toward the back of the end zone. Even though it looked like he had initially been beaten, a second effort to dislodge the football from Bryant’s hands worked.

Against the Redskins in Week 3, Collins picked up the much smaller Ryan Grant and chased him in coverage down the field to break up the pass as it arrived.

Spagnuolo has also featured Collins in his blitz packages, where the explosive safety can break off from coverage looks and rush the quarterback. Against the Eagles, he left what appeared to be man coverage on tight end Zach Ertz, instead rushing quickly through an open gap in the offensive line for the sack.

Then, on a third-and-7 early in the third quarter last Sunday, pressure from Collins forced Dak Prescott to rush his throw, and it fell incomplete.

No one thing has allowed Collins to make a big jump in his second season; instead, it’s been a combination of factors, ranging from an increase in speed and explosiveness to simply getting more experience in the Spagnuolo system. Collins said, “[My] confidence level is through the roof compared to where it was at the end of last year.” And this has manifested itself in big play after big play.

With a fully optimized Collins manning the backfield, the Giants have discovered just how big of an impact an elite safety can have for their defense. New York now has the capability to deploy Collins in so many roles that it makes it nearly impossible to game plan for this defense. Equally effective as a coverage player, run defender, and blitzer, he’s become their most valuable chess piece. The Giants doled out close to $200 million to bring in defensive difference-making free agents over the offseason, but they’ve gotten the most worth from a second-year safety making just over $700,000.