RENTON, Wash. — Just as the Seattle Seahawks are evolving offensively and finding success, they have another problem emerging.

In the last few weeks, Seattle can’t get off the field on defense. And it’s not the best time to be struggling on that side of the ball – about to go on the road, in a short week, to face Tom Brady and the New England Patriots on Sunday night.

In the past two weeks, Seattle has shown signs that the wear of its overtime tie with Arizona on Oct. 23 may be affecting its defense. Combined with an offense that seems to be abandoning its attempt to run the ball and control time of possession, the Seahawks defense has been asked to be on the field for an inordinate amount of time lately.

“We’re playing a little bit more ball but at the same time I think we’re doing some good things,” Seattle defensive end Cliff Avril said.

While the players say this is not an issue and Seattle Coach Pete Carroll is almost defiant in saying the amount of time the defense has spent on the field is a benefit, the statistics are telling a different story.

And the biggest indicator is on third downs.

“We’ve had 13 third-and-2 or less in the last two weeks. That’s really hard to win like you would like to on third down,” Carroll said. “We have to play better ball on earlier downs and then we have to get off when we have our chances. But it has been kind of a theme here allowing these third-and-shorts and not getting out of those. That’s really the focus.”

Over the past three weeks the Seahawks have allowed 58.4 percent third downs to be converted (31 of 53). Buffalo was 12 of 17 on Monday night and had 30 first downs, tied for the seventh most ever against the Seahawks in the regular season. The inability to get off the field on third down, combined with the Seahawks’ own struggles to sustain drives has led to three straight games in which opponents had the ball 36 minutes or more.

Arizona got it started when it dominated possession in the 6-6 tie. The Cardinals held the ball for 46:21 and ran 90 offensive plays. New Orleans followed a week later with 72 plays and 36 minutes of possession and on Monday night Buffalo ran 82 offensive plays and held the ball for 40 minutes.

It’s a recipe for exhaustion, even if Carroll doesn’t view it that way.

“I think we’re getting stronger,” he said. “If we’ve endured it, I think we’re in pretty good shape. If we can get a game of 60 or 70 plays, it’s going to seem like a lark. We’ll see if we can change it a little bit.”

The struggles on defense are troubling because the Seahawks appear to be morphing offensively and potentially exposing their defenders to even more time on the field. Seattle is 30th in the NFL averaging just 75.4 yards per game rushing and in Monday’s win had 26 passes and just 12 runs. No matter who is in the backfield, Seattle has been unable to establish the run and keep drives moving. Seattle has one drive longer than 6 minutes in the past five games and ranks 25th in time of possession.

“We have a lot of improvement to make and we’re just going to keep banging away at it,” Carroll said. “We know where we’re going, we’re just not quite getting on that track yet.”