The quarter mark of the regular season is when one- or two-game anomalies can begin to grow into year-long trends. This is when a sixth-round draft pick who has a good first game can prove himself to be a surprisingly productive starting quarterback. Or a long-time league doormat can show that it has truly become a defensive force to be reckoned with in the division ruled by the best coach-QB combo of all time.
Unfortunately, the flip side can also be true: This is when a disappointing first few weeks can morph into a seriously subpar campaign.
The six players below are not necessarily there yet -- they do still have most of the season to turn things around. But they definitely have fallen short of expectations at this point in 2019.
1) Kirk Cousins, QB, Minnesota Vikings
Simply put, no quarterback needs a commanding performance in a big win as much as Cousins does right now. In a Week 4 road loss to the Chicago Bears, Cousins averaged 6.5 yards per completion, was sacked six times and failed to complete more than two attempts that traveled 15-plus air yards. He's off to easily the worst start of his career since becoming a starter in 2015, hitting new lows in yardage (735) and TD-to-INT ratio (3:2) in the first four games of a season. It's hard to imagine Cousins' teammates -- like, say, a frustrated Adam Thielen, to whom Cousins later publicly apologized -- or even Cousins himself having much confidence in the Vikings' passing game if he can't step up and get it into gear. Minnesota's defense and the Dalvin Cook-led ground attack are good enough to propel a playoff run -- but only if Cousins and Co. can provide some semblance of an aerial threat and start hitting some deep balls. Otherwise, in the tough NFC North, this team is in trouble. Compounding all of this is the pressure that comes with being on Year 2 of the three-year, $84 million contract he signed with the team last year.
2) Von Miller, OLB, Denver Broncos
As a seven-time Pro Bowler who'd logged double-digit sacks in all but one of his previous eight NFL seasons, Miller had set an exceedingly high bar for personal performance coming into 2019 -- and expectations were raised even higher by the appointment of defensive mastermind Vic Fangio as Denver's head coach. Until his two-sack outing against Jacksonville in Week 4, Miller had been held without a sack in 2019, continuing a stunning sackless streak that stretched back through the final two games of 2018. It's not too late to turn it around; I should note that Miller's last extended stretch without a sack came from Week 3 to Week 5 last season, and he proceeded to finish tied for fourth in the NFL with 14.5 sacks. Perhaps Week 4 will put him on the upswing again -- although life will get much tougher for the veteran in the wake of fellow pass rusher Bradley Chubb's season-ending ACL tear.
3) Donte Moncrief, WR, Pittsburgh Steelers
With JuJu Smith-Schuster (17 catches for 258 yards) and James Conner (3.2 yards per carry and one rushing touchdown) struggling to produce in this Ben Roethlisberger-less season, there would seem to be a number of Steel City candidates for this list. But Moncrief could have played a crucial role in helping this offense stay viable in the early going. It's true that the free-agent signee has never hit 1,000 receiving yards in his career, but he was coming off a decent 2018 showing with the Jacksonville Jaguars in which he caught 48 passes at a clip of 13.9 yards per catch and chipped in three touchdowns. If Moncrief had provided a legitimate secondary receiving threat as the Steelers adjusted to life without former No. 1 Antonio Brown, Smith-Schuster would likely be performing much better. Instead, Moncrief displayed an alarming inability to catch the ball, infamously letting the second pass of Mason Rudolph's tenure as Big Ben fill-in bounce away from him and land in the arms of a Seahawks defender. Moncrief was inactive in Week 3 and did not receive a single target in Week 4. As of now, he has three catches for 7 yards to show for his 11 targets in 2019. Without a solid No. 2 option to demand defensive attention, it's too easy for Pittsburgh's opponents to simply roll coverage to wherever Smith-Schuster is on the field. Moncrief is looking like an atypical bust for an organization that tends to otherwise have a good eye for receiving talent.
4) Josh Norman, CB, Washington Redskins
One way to land on this list is to underperform relative to your contract, and that's the case with Norman, who is paid like a No. 1 cornerback (he's in Year 4 of a five-year, $75 million deal) but is not playing like one. So far in 2019, he's been beaten for four touchdowns in four games and allowed 16 catches on 24 targets (66.7 percent success rate), according to Pro Football Focus, while logging just four pass breakups and one pick. Norman never was fleet of foot -- his 40-yard-dash time being in the high 4.6-second range likely contributed to him falling to the fifth round in the 2012 NFL Draft. But he had the quickness and ball skills to make up for his lack of straight-line speed. Now, as a 31-year-old in his eighth NFL season, that quickness appears to be deserting him, and it's showing in his play.
5) Matt Ryan, QB, Atlanta Falcons
As the old saying goes, quarterbacks get too much credit for wins and too much blame for losses, and this applies to Ryan. He's not the main reason Atlanta has slogged its way to a 1-3 start behind a surprisingly listless offense (26th in points scored) and a defense that hasn't been able to keep opponents within striking distance (22nd in points allowed). Still, Ryan is a central figure, and he hasn't helped his cause by throwing six interceptions (with one fumble lost) through Week 4 after throwing seven total in all of 2018. As you'd expect of a classy person like Ryan, he's shouldered the blame for the Falcons' early troubles, saying after the Week 4 loss to Tennessee that he has to "take care of the football better than I have up until this point." But if this team is to make anything of this season, he's got to snap the offense out of its funk -- especially with the next four weeks including games against the Texans, Cardinals, Seahawks and Rams.
6) Adrian Peterson, RB, Washington Redskins
Peterson's season started on a bad note, with coach Jay Gruden making him a healthy scratch in Week 1 despite Peterson coming off a 1,042-yard effort in Washington in 2018. The veteran might still be in mothballs had young running back Derrius Guice not gotten hurt, as Gruden seemed to make it clear his preference was to roll with Guice rather than changing his offense to accommodate Peterson's downhill running style. (Though Gruden claimed to "love north-south backs.") After three games with Peterson on the field, the seven-time Pro Bowler leads the team in rushing attempts (33) -- but he's produced just 90 yards (2.7 yards per carry) and one touchdown. Perhaps it wouldn't be fair to expect a back of Peterson's age, and with his kind of mileage, to produce much. At this point, one wonders if, at 34, his illustrious NFL career is finally winding down.
Follow Gil Brandt on Twitter @Gil_Brandt.