LANDOVER, MD. – "The Longest Yard" was funny as a comedy. As a documentary title for the Vikings' consistent inability to gain 3 feet of NFL real estate during the free-falling 2016 season? Not so much.

"It's unbelievably frustrating," left guard Alex Boone said after the Vikings' running game stalled out yet again in a 26-20 loss to the Redskins at FedEx Field. "Converting third-and-1 [wins] that game."

The Vikings did use a four-tackle formation with a tight end and a fullback to actually score a running touchdown on third-and-goal at the 1-yard line in the second quarter. It was fulfilling, albeit short-lived, after being stuffed from the 1 on first and second downs.

"We call the two extra tackles we bring in the 'muscleheads,' " fullback Zach Line said of Nick Easton and Jeremiah Sirles. "That's a lot of weight in there. But … ."

But after that, the Vikings' short-yardage game looked as weak as it did while turning the ball over on downs inside the 10-yard line with only a yard needed in losses to Philadelphia and Detroit.

A 20-point second quarter erased a 14-0 first-quarter deficit. But the Vikings couldn't keep the lead because they couldn't convert their first two third-down situations of the second half.

"We try so hard, but we just can't get the yard," said running back Matt Asiata, who was stuffed on straight-ahead dive plays on those two third-and-1s. "We go in thinking we'll get it. Expecting we'll get it. But we don't."

While the Redskins were starting the process of kicking field goals on their first four second-half possessions, the Vikings offense was mostly sitting on the sidelines. Of the first 20 ½ minutes of the second half, the Vikings held the ball for only 5 ½ minutes with one first down as their 20-14 lead turned into a 23-20 deficit.

"It's kind of like [teams] know what we're doing now," Boone said. "You can run the ball only so well. Then teams are going to start pinning their ears back because they know we're passing the ball. It's a pain."

The Vikings had only 47 yards rushing on 21 carries. The 2.2-yard average came against a Redskins defense that went into the game ranked 31st in average yards allowed per carry (4.9).

Jerick McKinnon led the Vikings with 16 yards. Asiata had 13 yards on nine carries, including a 1-yard loss on the second third-and-1 of the second half. The Redskins clearly knew what was coming and executed a well-timed run blitz to blow the play up.

If not for receiver Adam Thielen's 11-yard sweep, the Vikings would have averaged 1.8 yards per carry. And that still wouldn't have been a season low for the 31st-ranked run game. In nine games, the Vikings have topped 100 yards rushing only once and have yet to average more than 3.5 yards per carry.

And if all of that weren't bad enough, left tackle Jake Long went down with what could be a career-ending Achilles' tendon tear on a third-and-17 incompletion with 11 seconds left. That forced Sirles into the game for the final snap.

About two months ago, Sirles was on the roster bubble. Now, during this injury-riddled season, he has played every tackle and guard spot in a game.

As the fourth guy to play left tackle this season, he gave up the game-clinching sack to Preston Smith.

"He just beat me around the edge," Sirles said. "There's nothing I can say about it. I'm beating myself up about it."

Boone said he'll go to line coach Tony Sparano and volunteer to play left tackle. Boone has played the position before, albeit sparingly, and has the build for it. Sirles would then step in at left guard, where he has one start this season.

Maybe that helps the pass protection. But only if the Vikings can find a way to shorten "The Longest Yard."

"You can keep saying you played so tough until it doesn't count anymore," Boone said. "You got to get those third-and-1s."

Mark Craig is an NFL and Vikings writer. Twitter: @MarkCraigNFL E-mail: mcraig@startribune.com