ASHBURN -- The problem didn't stop the Redskins at Tampa Bay, where they moved the ball, produced points and won. A week later it did. With the Redskins facing a powerful offense, they needed to control the ball and score points.

The offense failed on both counts. There's a reason: It couldn't convert on third downs. But it wasn't a one-week issue. Against Tampa Bay, for example, the Redskins rolled up 474 yards and 24 points but converted two of 11 third downs. Against the Falcons they were 1-for-9.

It gets worse. For the season, the Redskins rank last in the NFL, converting just 14 of 60 third downs (23.3 percent). Yet the offense ranks seventh in yards per game and eighth in points.

"Moving the ball hasn't been an issue," Redskins offensive coordinator Kyle Shanahan said. "Third down is what stopped us. ... We feel confident when we move those chains, we'll get more points."

His dad, also the coach, was more succinct. And obvious.

"It's an area we have to get better at," Redskins coach Mike Shanahan said.

Third-and-longs are a major issue. The Redskins have faced third-and-7 or longer on 17 of 23 third downs the past two games combined. One ended with a personal foul on third-and-19, another resulted in a 77-yard touchdown pass and a third gained 30 yards on a trick play. They also kicked a game-winning field goal on third-and-8 at Tampa Bay.

It has been worse the past two games, but it follows a trend for the season. Of their 60 third downs, they've needed at least seven yards on 38.

"It's not always third down. It's what happened on second down to get you into a third-and-long," Kyle Shanahan said.

The problem? Washington has struggled on third-and-short as well. They've faced third-and-3 or less 11 times and converted only three into first downs: one of five when running and two of five when passing.

Having a rookie quarterback plays a role, too. Griffin's third-down passing numbers aren't good when it comes to converting them into first downs. His passer rating on third down is a solid 86.6. He has completed 21 of 34 passes for 190 yards. His 5.59 yards per attempt on this down is topped by 25 other quarterbacks (with at least 17 attempts).

But there's a flipside. He's one of eight quarterbacks not to throw an interception on this down. Nor has he been sacked. So he's at least making safe and quick decisions. Of the 22 times he has faced third-and-7 or more, Griffin has completed 14 passes -- but only two went for first downs. He often throws underneath the coverage, hoping for a receiver to run for a first down. Last week, he had two passes dropped on third down.

"When teams, on third-and-7, they drop guys in deep coverage, we have to trust each other that if I throw the checkdown, you're going to get the first down or extremely close to it," Griffin said. "There are times to break the pocket and make plays, and then there are times you just have to take the checkdown, take what they're giving you and just know that the guy you're throwing to is going to try as hard as he can to get the first."