– After the Vikings blew a lead in Chicago in September, their defensive starters dressed slowly after the game. They spoke quietly, using gallows humor as salve. They shook their heads, commiserated, and, in interviews, hinted at dissatisfaction with the defensive play calls that may have cost them an important victory.

Sunday, the defensive veterans reprised that scene. They again looked confused, if not dismayed, on a last-minute, game-losing drive. They lingered in the locker room after their teammates had left, slowly knotting ties and softly grumbling. This time, they spoke their minds.

“There’s some things that are going on internally that are not allowing us to close out games,” defensive end Brian Robison said.

“I think we could have been in better situations at the end of the game,” defensive tackle Kevin Williams said.

For most of the Vikings’ 27-23 loss to the Cowboys at AT&T Stadium, the Vikings’ front four hassled Tony Romo into mistakes, helping protect a secondary winnowed by injuries.

With the Vikings leading 23-20, the Cowboys took the ball on their own 10 with 2 minutes, 44 seconds remaining. The Cowboys scored in nine plays. Romo threw the ball nine times, completed seven passes and was not sacked.

Williams and Robison noted that the Vikings coaches, presumably defensive coordinator Alan Williams, abandoned the plan to pressure Romo. The play calls required defensive linemen to drop into coverage. Romo, given time, shredded the Vikings secondary.

At the end of the Bears game, the Vikings secondary was left out of position, leading to the winning touchdown pass. On this Sunday, an angry group of defenders seemed unhappy with the work of both play-callers: Williams and offensive coordinator Bill Musgrave.

Musgrave’s play-calling is often curious. Sunday, he at least emphasized the running of reigning league MVP Adrian Peterson, who rushed for 140 yards and a touchdown on 25 carries.

So when the Vikings got the ball with 4:29 remaining, holding a 23-20 lead, you could almost hear the Vikings defenders calling from the sideline for Peterson to continue to batter a worn-down defense.

Instead, Musgrave called for a pass. Ponder threw incomplete, on a deep pattern to Greg Jennings, a low-percentage play. The clock stopped. Peterson rushed for 1 yard on second down, and then Ponder, facing third-and-9, scrambled for 4 yards.

The Vikings punted, the Cowboys drove, and the Vikings defenders complained.

“You think we would run, to run the time out,” Williams said. “But I don’t coach offense. I just have to play what they call on defense.”

Players, like most employees, probably complain all the time. Wide receivers complain constantly. This is different.

Robison and Williams are two accomplished and highly respected players. The Vikings just rewarded Robison with a contract extension. Williams will receive Hall of Fame consideration. They are leaders.

When players like that complain publicly after holding their tongues for weeks, they are sending verbal flares in the direction of the head coach and front office. They want changes to be made.

As badly as the season has gone, the Vikings have plenty of good people in place. Their general manager has drafted well at every position other than quarterback and cornerback. Their head coach has the respect of the locker room. They have the best running back in football, and a dozen other players any NFL team would want.

Musgrave and Williams have cost the Vikings at least three games. They may not be keeping the Vikings from contending for the playoffs, but they have prevented the Vikings from approaching respectability.

Sunday’s near-upset was proof that Vikings players haven’t quit on their head coach, but that some of them would like to stage a coup against his top assistants.

If Frazier wants to survive as head coach, he will effect change, whether that means dictating play calls to his coordinators, or replacing them.

Frazier has hired three coordinators since he took over in 2010. Fred Pagac failed and was demoted. Musgrave and Williams are failing this season.

Coaching without quality coordinators is like driving at night without headlights. It’s time for Frazier to open his eyes to what his players plainly see.