RENTON — As good as the Seattle Seahawks’ defense has been the past two games — six points and just 368 yards allowed in victories over Arizona and San Francisco — coach Pete Carroll said he thinks it can get better.

“The fact that we are just starting to hit stride now, I think our best football is still ahead of us,’’ Carroll said Monday during his regular meeting with the media.

It might have to be as Seattle faces a Philadelphia team on Sunday that on paper is the most daunting offensive challenge left for the Seahawks in the regular season.

The Eagles, in their second year under former Oregon coach Chip Kelly, are fourth in the NFL in both points scored per game (31.3) and yards gained per game (416.2), keys to a 9-3 record that is tied for the best in the league.

And, as Carroll noted, “There is tempo to it, as well.’’

Indeed, while Kelly has made some adjustments to scheme and style since leaving Oregon, one thing that hasn’t changed much is the speed with which his offense plays.

The Eagles have run 875 plays, 32 more than any team in the NFL (the Colts are second with 843), an average of 72.91 per game.

Seattle, by contrast, has run 746 plays, or 62.1 per game.

Carroll rightly points out that Seattle has had success against up-tempo offenses — the Super Bowl victory over Denver being the most notable.

So, preparing for the Eagles won’t necessarily create a different week of practice for Seattle.

“You have to prepare, in modern football, to be in the no-huddle mode,’’ Carroll said. “So we always prepare for that. So it’s not a big change for us, how much they are able to push the tempo. We are ready for that. We have been in that mode for the last couple of years now just because you have to be.’’

As fast as the tempo might be Sunday, suddenly the stakes are high in a game whose importance has increased markedly over the past few weeks.

The Eagles, who won Thursday at Dallas 33-10, are tied atop the NFC standings with Arizona and Green Bay. Arizona has the No. 1 seed at the moment due to a 7-2 conference record, with the Eagles next at 6-2 and Green Bay third at 5-3 (NFC South leader Atlanta, at 5-7, is the No. 4 seed, as division champs are the top four seeds regardless of record).

Seattle, meanwhile, is the No. 5 seed this week at 8-4, earning tiebreaker edges on both Detroit and Dallas, both also 8-4.

But where just earning a wild-card berth might have seemed good enough two weeks ago when they left Kansas City with a 6-4 record, the Seahawks suddenly are in realistic reach of larger goals.

In fact, thanks to its two victories in the past eight days while the Cardinals were losing two games (Seattle, and Sunday to Atlanta), Seattle suddenly is back in control of its own destiny for winning the NFC West. If Seattle sweeps its last four games (including a rematch with Arizona on Dec. 21 on the road) then Seattle would take the division title and hold at least the No. 3 seed.

Carroll says the fact that the team’s playoff fortunes have changed so quickly, though, doesn’t really change the team’s approach.

Still, he allowed that “one of the things you love in competition is when you control your own future and we have an opportunity to do that.’’

NOTES

• Cornerback Loucheiz Purifoy, signed by Seattle on Friday, was waived Monday after failing his physical.

• CB Jeremy Lane, who missed the 49ers game with a glute injury, should return this week, Carroll said. TE Cooper Helfet is day-to-day with an ankle injury, Carroll said.

• C Max Unger, out the past two weeks with knee/ankle injuries, won’t play against the Eagles but might be able to return for the Dec. 14 game against the 49ers, Carroll said.

• When asked how he would feel if owner Paul Allen tweeted out after a defeat that the loss was unacceptable, Carroll smiled and said, “Our owner would never do that.” The question came in reference to a tweet sent out by 49ers owner Jed York after the defeat Thursday to the Seahawks in which York apologized to fans and called the loss “unacceptable.”

Bob Condotta: 206-515-5699 or bcondotta@seattletimes.com. On Twitter @bcondotta.

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