Prior to the 2015 NFL season, we published an article on Pro Football Focus’ website that explained why Indianapolis Colts quarterback Andrew Luck ranked just outside our top 10 QBs entering the year. It inspired plenty of angry comments from Colts fans and others, given that Luck was considered a borderline top-5 NFL QB at the time.

The argument of the article was not to deny Luck’s immense talent and potential – it instead was to point out that his play to that point in his career didn’t yet merit a ranking ahead of other more accomplished QBs. His best games stood right up there to the league’s elite QBs – the problem was he had as many poor games to balance things out. Luck then struggled mightily in 2015 (he earned the lowest PFF grade of any NFL quarterback) prior to a season-ending injury, and the Colts missed the playoffs.

Indianapolis is 3-5 heading into its Week 9 road trip to play the Green Bay Packers, and a loss in that one will again put the Colts at serious risk of missing the postseason.

But there’s a big difference this year: Luck is actually playing like a top-5 QB, and the Colts’ issues at other roster spots are causing them to possibly waste what to this point has been the best season of Luck’s young career.

Luck currently ranks third in the NFL in PFF QB grades

Luck’s 88.9 grade (on a 1-100 scale) through eight weeks this season ranks only behind Tom Brady and comes in just shy of the highest he’s ever earned over the course of a full season, which was an 88.4 back in 2014.

But it isn’t a stretch to make the argument this has been his best season as a pro so far, having earned excellent grades in two games thus far, above-average grades in four more and just two poor grades on the season.

Season Adj. comp. % Deep QB rating QB rating under pressure % of pressured dropbacks
2016 75.6 (10) 125.5 (2) 74.5 (7) 43.3 (1)
2015 65.0 (37) 97.7 (12) 45.3 (34) 39.6 (6)
2014 73.3 (16) 116.5 (4) 74.8 (8) 36.2 (8)
2013 70.6 (20) 83.6 (10) 62.3 (15) 37.5 (10)
2012 67.4 (25) 82.0 (15) 56.8 (17) 38.1 (4)

He has never been more accurate than he has been this season, with an adjusted completion rate of 75.6 percent (removes drops, throwaways and passes on which he was hit as he threw) that ranks 10th in the NFL this season. He has never been more productive on his deep balls, earning a 125.5 passer rating on throws of 20-plus yards downfield that ranks second in the league. He has also never owned a higher rank among his peers in passer rating when under pressure by the pass rush, earning a 74.5 rating this season that ranks seventh in the league.

All of those measures tell the story of a quarterback playing some of, if not the, best football of his career. And in a season largely devoid of elite-level QB play (with the notable exception of post-suspension Tom Brady), that’s been good enough for Luck to rank second among all quarterbacks in PFF grades.

Luck has been under pressure on 43.3 percent of his dropbacks this season – most in the NFL

As shown in the table above, Luck has never had a season in which he wasn’t pressured on less than a third of his dropbacks, or didn’t rank among the 10 most pressured QBs in the league. But it’s never been as bad for him as it has been this year, as he has been pressured on a league-high 43.8 percent of his dropbacks.

To be fair, the Colts’ style of offense with Luck under center doesn’t do their offensive linemen any favors in that Luck holds onto the ball about as long as any quarterback in the league. His time-to-throw average of 2.90 seconds is the third-slowest in the NFL this season. But even in PFF’s pass-blocking grades, which take into account the amount of time an offensive lineman has to hold his block in pass protection, the Colts rank third-worst in the league.

Moreover, the Colts’ offensive supporting cast as a whole hasn’t been an area of strength this season. Guard Jack Mewhort held his own prior to being injured, rookie center Ryan Kelly has shown promise, and left tackle Anthony Castonzo and wide receiver T.Y. Hilton both rank among the top 17 players at their position groups this season. But as you can see from the graded lineup graphic below, Luck is having to do a lot of heavy lifting on his own this year:

This is backed up by the team’s receiving stats, as Luck has had to deal with the NFL’s 11th-highest drop rate, which includes an NFL-leading seven drops when under pressure – meaning Luck isn’t just having to deal with pass-rushers constantly disrupting his pocket, but when he is able to get the ball out and on-target to his receivers, they haven’t been able to consistently hang on to the ball.

But as much as his supporting cast has struggled, the Colts’ defense has been even worse

Luck’s supporting cast on offense has certainly presented a challenge for him, but the Colts’ issues on defense have been far more noticeable. They currently rank dead-last in the NFL in overall defense grades, including ranking last versus the run and last in coverage grade (the pass rush is the “best” element of the defense, ranking 24th).

Not a single player among the Colts’ starters or part-time starters on defense has a PFF grade over 80.0. While there is some promise for the future in the form of defensive lineman Henry Anderson, a third-round pick from 2015, generally speaking there is a glaring lack of talent on this defense, and little reason to expect the team to be able to turn that around as the season progresses – including this weekend against an improving Packers offense.

What it means for this season

If there is an optimal NFL division for making a late-season run and reaching the postseason, it’s the AFC South. The division-leading Houston Texans, at 5-3, are playing without their best player in defensive lineman J.J. Watt and are starting a QB in Brock Osweiler who ranks second-to-last in PFF grades. The second-place Tennessee Titans (4-4) are starting one who ranks fifth-to-last in Marcus Mariota, and the last-place Jacksonville Jaguars (2-5) just fired their offensive coordinator after an embarrassing loss to Tennessee.

Those problems among the competition combined with a quarterback playing like one of the five best at his position this year should be enough for a division title, but the significant issues at every other position group on the Colts’ roster could lead to their wasting one of the better QB performances of the 2016 season.

Jeff Dooley is the Editor in Chief of Pro Football Focus and a contributor to The Washington Post’s NFL coverage.