AJ Mast/Associated Press

Head coach Chuck Pagano and general manager Ryan Grigson haven't done enough.

The Indianapolis Colts are set to miss out on the playoffs for the first time in four seasons. Having won 11 games in each season since drafting quarterback Andrew Luck in 2012, the Colts will slump to a .500 or below record this season. Losing to the Houston Texans this past Sunday put the Texans in pole position to win the AFC South.

Because of their 6-8 record, the Colts can't compete for a wild-card spot in the AFC.

In previous seasons, Luck has dragged a significantly flawed Colts roster to the playoffs with his exceptional play. His output and the quality of the division allowed them to be so successful during the regular season (the Colts had a 16-2 record against AFC South opponents from 2012 to 2014).

After Luck's rookie season, the Colts went 12-0 against AFC South opponents.

The Colts had a win percentage of 89 in divisional games during those three seasons. They were 17-13 against all other opponents, a win percentage of 57. Importantly, while stockpiling victories, the Colts were also regularly being blown out in games when they lost.

On three occasions, Indianapolis lost by 35 or more points. One of those losses came in the playoffs against the New England Patriots. Indy lost one more game by 30 points and lost by 20 or more points on nine separate occasions.

Beating bad teams in the AFC South made the Colts look like a much better team than they have actually been. Playoff victories against similarly underwhelming opponents in the weaker conference have done the same.

The Colts' marquee victory came against the Denver Broncos in 2014, but that Broncos team was playing with an injured Peyton Manning who repeatedly missed wide-open receivers for big plays downfield. The Patriots didn't miss out on those opportunities the following week when they blew the Colts out again.

Luck's presence on the roster and the quality of the team's division were distorting the results used to measure the quality of Pagano's and Grigson's work.

In 2015, those aspects of the team disappeared. Luck entered the season playing poorly. He threw seven interceptions in three games while averaging 6.5 yards per attempt before being sidelined through injury in Week 4.

Luck returned for four games but struggled again before being sidelined because of injury once more. Without their All-Pro-caliber quarterback playing to his potential, the Colts couldn't turn to any other facet of their team to win games.

Pagano's philosophy when he took over the Colts was to build a team that could run the ball and stop the run. In theory, these are both things you want to be able to do. However, the Colts have been trying to build a team that would succeed in different decades, not the one we currently exist in.

Furthermore, the head coach's thought process to support this philosophy is flawed. From Pagano, per Craig Kelley of the Colts' official website:

If you just go by numbers, you could argue that we're not there yet. We'll never change that mindset. Until they run me out of here, that'll be our mantra. ... (In) our game, New England rushed 46 times. In all three other (divisional) games, the winner(s) all rushed for 30 times and averaged (144.3) yards. The losing teams averaged 88 yards rushing. So, will we ever change? No.

What Pagano fails to realize is that winning teams run the ball more because they are trying to run out the clock when playing with a lead. The number of attempts doesn't actually help create wins; it's the opposite.

Even if Pagano's philosophy were a smart one with a great talent at quarterback, Pagano and Grigson have failed to build the offense they imagined.

Power running has been a staple of the Colts offense regardless of who has been their coordinator over the years. They have never been a strong running team, often just sacrificing downs at the beginning of drives for one- or two-yard gains.

So far this season, the Colts have ranked 32nd in rushing DVOA (defense-adjusted value over average), a Football Outsiders metric that measures efficiency on a snap-by-snap basis.

When Luck went down, the Colts needed 32-year-old Frank Gore and the running game to carry the offense because Matt Hasselbeck isn't talented enough to lead this supporting cast. He probably wouldn't have been talented enough even during his prime, which was a long time ago for the 40-year-old veteran.

Indianapolis signed Gore to be the focal point of the running game. He has proved to still be an effective back but is more reliant on his offensive line than ever. However, the Colts offensive line isn't good, and Gore is averaging 3.6 yards per rush this season on 226 carries.

He had never averaged below 4.1 in a season during his career before this year.

Credit: NFL.com

Against the Texans in the Colts' biggest game of the season last week, Gore averaged 2.8 yards per attempt. This wouldn't have come as a surprise; the Colts have averaged 4.0 yards or more as a team just three times all season.

Gore carried the ball 16 times against the Texans, and according to Pro Football Focus, exactly half of those gained one yard or fewer.

Per PFF, Gore has broken 30 tackles this season on rushing plays, tied for 12th-most in the NFL. Despite that, he is still only averaging just over two yards after contact. That is because he is consistently crowded out while executing failed power-running plays.

Credit: NFL.com

The above play is indicative of how the Colts have blocked running plays during the Pagano era. Multiple blockers have been quickly beaten in their blocks, the right guard and the fullback, leaving Gore with nowhere to go.

Even when Trent Richardson was so slow he wouldn't be able to find holes created directly in front of him, the Colts weren't giving him options on a consistent basis.

Despite their futility running the ball, the Colts have stuck with this philosophy. It's not simply about how many plays they ran the ball on, but it's how they built their passing plays, expecting Luck to make downfield throws off play action that rarely worked because they couldn't run the ball in the first place.

Pagano has changed his offensive coordinator, firing Pep Hamilton in favor of Rob Chudzinski, but maintained the same stone-age philosophy toward building an offense. He appears to be fully committed to that philosophy, and so long as he is, it will prevent the Colts offense from getting close to its potential.

The other side of Pagano's philosophy, stopping the run, has not been something his team has achieved either.

When the Patriots have blown the Colts out in previous years, they have done so by running right through their front seven. In individual matchups, the Colts can be badly exploited by opponents, but their efficiency as a whole has remained average.

Colts run defense rankings by DVOA Year Ranking 2012 32nd 2013 22nd 2014 19th 2015 14th Source: Football Outsiders

In a pass-heavy league, a defense that is so committed to stopping the run has to be a dominant one. You have to be able to force opponents to become unbalanced and throw from unfavorable down-and-distance situations.

The Colts obviously aren't dominant, while their secondary lacks the speed to match up to the versatility and talent of opposing passing games.

Most criticism of Grigson surrounds his decision to trade with the Cleveland Browns for Richardson. It was obviously an awful decision and the highest-profile move he has made, but his most egregious mistakes have actually come on the other side of the ball.

Richardson was once a talented player even if he shouldn't have been a first-round pick and didn't live up to expectations. Many of the players Grigson has added to his defense have been overpaid or overstretched in their roles.

Over recent years, the main issue with the Colts defense has been its lack of speed over the middle of the field. Instead of drafting and developing safeties or linebackers, Grigson has invested in past-their-prime veterans who were never great players in the first place.

All of D'Qwell Jackson, Mike Adams and LaRon Landry were signed to play pivotal roles in the defense despite being inadequate players.

Adams is the one who stands out the most because he has 10 interceptions over the past two years. He has 10 interceptions because he is disciplined in his assignments and has good ball skills, but the 34-year-old can't cover enough ground to play the role the Colts ask him to.

Interceptions are highlight plays that draw a lot of attention, but on a snap-by-snap basis, Adams creates more negatives with his lack of range than he does positives.

The Colts' pass defense has been atrocious this season. It has given up 267.2 passing yards per game, 29th in the league, while ranking 17th in Football Outsiders' DVOA, 20th before facing T.J. Yates in Week 15. A huge reason for that is its lack of a consistent pass rush or the speed to cover the middle of the field.

Grigson built that limited pass rush. He is no longer working with players he inherited from the previous regime. The defensive front he built ranks 28th in the NFL in sacks through 14 games. It has 25—1.8 sacks per game.

When you look at what Grigson and Pagano have done on the surface, the Colts look like a team that is headed in the right direction. They are progressing in terms of wins and losses each season and only dropped off in 2015 because they were forced to play without their starting quarterback.

Looking closer at the minutia of their era in Indianapolis suggests that both coach and general manager have been net negatives.

Building a strong team in Indianapolis is about to get much more difficult because Luck's salary is only going to continue to rise. His next contract will take up a huge percentage of the cap, affording the franchise less margin for error with the moves it makes.

Expecting Grigson and Pagano to build a contender in the future would be a baseless expectation. They haven't done enough to this point in their respective careers to suggest they know what they are doing.