IRVING, Texas -- The Dallas Cowboys find themselves in last place in the NFC East and tied for the worst record in the NFC because they took an arrogant approach to the offseason.

It was easy to do because they finished 12-4 and won the division behind the game’s best offensive line in 2014. DeMarco Murray produced a franchise-record 1,845 rushing yards and Tony Romo had never played better when it mattered most.

And that’s why they believed their own hype.

The Cowboys pride themselves on making decisions collectively, so you can blame the quartet of owner/general manager Jerry Jones, vice president Stephen Jones, head coach Jason Garrett and scouting director Will McClay in any order you choose.

Darren McFadden has been solid this season -- with 798 yards while averaging 4.2 yards per carry -- but the Cowboys miss DeMarco Murray's production. AP Photo/Jeffrey Phelps

This season’s demise began with the foolish decision to make Brandon Weeden the Cowboys’ backup quarterback, because it’s obvious Garrett and offensive coordinator Scott Linehan had zero confidence in Weeden.

They gave him a Pop Warner game plan, then wondered why he didn’t produce before demoting him as starter after three winless starts. Matt Cassel, Weeden’s replacement, was acquired the week Romo broke his collarbone and the Cowboys knew they would need a starter for nearly two months.

Cassel has a 1-5 record as a starter, with five touchdowns, six interceptions and a 73.5 passer rating overall this season. He has flunked a quarterback’s most important job, which is getting the team into the end zone.

The Cowboys have scored one touchdown or less in four of his six starts. Pathetic.

A lot of the Cowboys’ offensive issues besides the obvious absence of Romo can be traced to the team's negotiating tactics with Murray. Clearly, the Cowboys were afraid of his age and his workload, which included more than 400 touches in 2014, so there was no way they were going to give him the five-year, $40 million deal he received from Philadelphia.

Matching Philadelphia’s deal wasn’t the problem. The Cowboys never really gave Murray a legitimate offer until free agency began. Everybody knows that if you allow a player to reach unrestricted free agency, the odds of him returning are virtually nil.

The Cowboys figured their offensive line was so good that even Joseph Randle, released after Week 6, and a running back by committee could get the job done.

They haven’t.

The running game may rank in the top half of the NFL, but it has been unreliable all season. The Cowboys have struggled in short-yardage situations and haven't controlled games with their running game the way they did last season.

The inconsistent running game has affected their ability to be productive with play-action passes and their deep passing game. See, it all works together.

Ignore the stats, which say the Cowboys have rushed for a 4.4 average on 346 carries and Darren McFadden has 798 yards and a 4.2 yards-per-carry average. If you’ve watched the games, you know the truth: They miss Murray -- or somebody like him.

The Cowboys eschewed selecting a runner in the best running back draft in years last spring, but it’s clear they need a starter. McFadden has been solid, but this team needs more than that because it wants a dominant running game.

In the process, the Cowboys have found out this line isn’t so good that anyone can gain 1,300 yards running behind it. You could not convince them of that last spring.

Part of the problem with the running game is the offensive line hasn’t been nearly as good as it was last season. There have been too many whiffs and too many average performances.

It’s not that Zack Martin, Tyron Smith or Travis Frederick -- the core -- have played poorly, because they haven’t. They’ve been really good in a season in which the Cowboys needed them to be great to compensate for Romo’s loss.

Bill Callahan is one of the league’s best offensive line coaches, but he and Garrett had a frosty relationship. Frank Pollack, Callahan's former assistant and the Cowboys' new line coach, will probably be among the first scapegoats at the end of this season.

There’s always a scapegoat or two when a season that began with Super Bowl aspirations ends with a top-10 draft choice.

The Cowboys handling of Dez Bryant's contract negotiations also proved to be one of the big mistakes of the offseason. When it was all said and done, the Cowboys essentially gave Bryant the same money he wanted when negotiations began.

Talk to enough folks in the front office and they’ll admit the club would’ve been better served paying Bryant in March so he could’ve been a full participant in the offseason program.

Instead, he missed all of the offseason minicamps and OTAs, so no one should’ve been surprised when he strained a hamstring early in camp that forced him to miss the entire preseason.

He broke his foot in the first game of the regular season and missed five games before rushing back. Watch him play, though, and it becomes clear he hasn’t been right much of the season.

His numbers are pedestrian and he’s had just one 100-yard game this season, which is awful for a player who averaged 91 catches, 1,312 yards and 14 touchdowns over the previous three seasons.

The Cowboys figured he was good enough to miss the offseason and still perform at the highest of levels.

It’s just one more arrogant offseason decision the Cowboys made that has turned what was supposed to be a season to remember into one to forget.