It takes time for a corner to develop. From 2011 to 2015, the average experience level of a pro bowl cornerback hovered around 5.7 years. Only 7 of the 41 pro bowl spots in that time (17%) were occupied by players with two years of experience or less, and more than half of those spots (23, or 56%) went to players with six years of experience or more.
Without context, those numbers are pretty meaningless, though. Across that same time, the average experience level of pro bowl wide receivers is a full year less (4.7 years), and 27% of pro bowl spots went to players in their first two years. Meanwhile, only 39% of the spots went to players with six or more years of experience.
It seems like experience matters to the defender. This is validated with a quick glance at outside linebackers, but even that position is more welcoming of youth than cornerback. Twenty-two percent of outside linebacker spots went to players in their first two years (8 of 36), and only half of the spots went to players with 6+ years of experience.
With that little bit of background out of the way, let's consider Kyle Fuller. After a strong start in early 2014, Fuller struggled toward the end of his rookie season. Likewise, Fuller had a mixed 2015 campaign, and while he faced some criticism, it's worth looking at what he actually accomplished by putting him into context compared to his team and his peers.
The Chicago Bears want us to know, courtesy of their season-ending review, that since coming into the league in 2014 Kyle Fuller is one of only four players in the NFL to have at least 6 interceptions and three forced fumbles (with Mike Adams, Josh Norman, and Earl Thomas being the other three). He also led the 2015 team in interceptions (although he only had two of them) and was second on the team with passes broken up (with 15). While fans might want both of those totals to be higher, it's nice to know that the team's first-round cornerback is acting like a first-rounder and leading the team in a couple of stats.
There are other sources to consider, as well, that have more reason to be critical of Kyle Fuller than his own team's review book. I have to admit that I do not particularly care for Pro Football Focus, given some aspects of their methodology, but those that do care might be pleased to learn that "From Week 3 on, Kyle Fuller earned the 14th-highest coverage grade among corners last season." In fact, while PFF was (understandably) down on the Bears secondary, they certainly liked what they saw from Fuller. For a second-year player to rank in the top tier of a group (PFF ranked over a hundred corners) is reassuring.
The same surge in productivity (or rather, anti-productivity) noted by Pro Football Focus is also matched by conventional stats, in that during the seven-game stretch from the bye week to the mid-December, Fuller allowed a passer rating of just 39.1. Likewise, after Week 6 he went without drawing a penalty. As noted, he got off to a rocky start last season. Still, he settled into strong play.
However, there's another number that is more interesting to me, and it comes from Football Outsiders. According to them, Fuller allowed only 5.7 yards per target, which was good enough for 14th among qualifying corners. Additionally, Fuller was only targeted on 17.3% of passes, good for 15th in the NFL. In other words, as the year went on Fuller was targeted less often and when targeted, he kept those plays from becoming meaningful. His raw production (like interceptions and passes defensed) were down in 2015, but opposing teams also stopped targeting him. One of the best compliments that an offense can pay a defender is by going somewhere else, and if Fuller's volume stat-line suffered for it, that's barely his fault. If anything, the fault belongs to the rest of the Bears' secondary, which made it reasonable to simply ignore Fuller.
Using multiple metrics from multiple sources, Fuller is producing like a first-round pick. His fellow first-round cornerbacks from 2014 are Justin Gilbert, Darqueze Dennard, Jason Verrett, and Bradley Roby. Across two years of play, Fuller leads them all in interceptions and ties Roby for the lead with forced fumbles. He's also second in passes defensed with 19 to Roby's 24. Verrett is the only pro bowler among this group, and while he was better in than Fuller was last year, he was also on a better defense overall.
Expectations: High. Fuller seems to have made progress last year, and the difficulties of his position favor more experienced players. For his second year with a real defensive coordinator in town, there's every reason to expect that, barring injury, he will continue to improve.