Why rookie CB Ronald Darby was one of 2015's top 101 NFL players

[Editor's note: Throughout this week, PFF will be releasing its list of the 101 best players of the 2015 season. Bills CB Ronald Darby finished the year at No. 82 on our list; click here to see 76–101.]

As the seventh cornerback taken in the 2015 NFL draft, Ronald Darby wasn’t viewed as the best CB in the class coming out of college. However, that's exactly what he turned out to be in his rookie season. Darby didn’t impress in the preseason, but he turned it around immediately for the start of the regular season, excelling from day one to become the best coverage player on the Bills’ defense.

Buffalo cornerbacks did not track receivers last year, so Darby spent the majority of his snaps at left corner. Because of that, he did not always face the top receiving threats of the opposing offense, but he did fare well when lined up against them, particularly early in the season. In Week 1 against Andrew Luck and T.Y. Hilton, Darby held Hilton to two catches for 23 yards on four targets while picking off Luck once and breaking up another pass. The following week, Tom Brady targeted Julian Edelman and Rob Gronkowski nine times into Darby’s coverage. He allowed just three catches for 48 yards and broke up one pass. Week 4? One 8-yard catch on four targets to Odell Beckham Jr., and another pass defense.

Darby did have lesser games, naturally; he allowed two touchdowns in back-to-back matchups against Kansas City and Houston, but those were also the only four touchdowns he allowed all season, with two coming from tight ends. In total, he earned below-average overall grades in just three out of 15 games. Even with the occasional struggles, he was by far the most consistent of the rookie cornerbacks.

Darby put together a stellar performance for a rookie that earned him PFF's Defensive Rookie of the Year award and runner-up for our overall Rookie of the Year honor (Jameis Winston took home the top honor). However, it wasn’t just his rookie peers he out-performed. Darby’s 86.0 coverage grade tied for seventh-best among all cornerbacks in the league. He also finished any given week among the top three cornerbacks in coverage grade on three occasions.

Over the course of the season, Darby allowed 660 receiving yards in spite of being targeted 105 times, the fifth-most of any defender in the league. The 54.3 completion percentage allowed into his coverage was the 17th-lowest among NFL CBs. Darby notched only two interceptions, but he still proved capable of making plays on the ball with 13 pass breakups, tied for fifth-most in the league. He also had two or more combined interceptions and pass breakups in six games. While his work in run defense wasn’t anything special, he did earn a positive grade and was far from being a liability, as can be common with young cornerbacks.

In all, Darby had an exceptional year at a position that can be difficult for players to adjust to as rookies. Even though he was a step below the elite players at the position, it does not diminish his performance. He still has plenty of room for improvement going forward, but for now, his performance ranks him 82nd on our list of the top 101 players of the 2015 season.