By Matt Dolloff, CBS Boston

BOSTON (CBS) — A hallmark of Bill Belichick-coached Patriots teams has always been to gradually improve over the course of the season to the point where they’ve ironed out all the wrinkles by the time they get past Thanksgiving. Unfortunately, that slow-build hasn’t quite materialized on the defensive side of the ball this season – in fact, it may have gone backward.

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Regardless of the talent lost on the Patriots defense, the unit simply played poorly at all levels on Sunday night against the Seattle Seahawks. The slow-build would presumably turn into a sense of urgency to turn the defense around, especially for an upcoming stretch of should-win games in which the Patriots absolutely must avoid a slip-up.

The 2015 Patriots season was arguably doomed by one such slip-up, the Week 12 loss to the Philadelphia Eagles at Gillette Stadium. Chip Kelly’s Eagles stymied the Patriots on special teams and scored 35 unanswered points after the Patriots’ ill-advised mortar kick. The Patriots ended up losing home-field, something they would gain a huge advantage in having for a potential AFC Championship Game instead of having to travel to a tough environment like Denver or Kansas City.

Safety Devin McCourty made it clear that the Patriots have turned the urgency up after losing to the Seahawks, which apparently woke them up to the problems they need to fix quickly as they approach the final stretch of the regular season.

“Obviously we’ve got some things we need to work on, coming off a loss. You definitely go through it a lot closer than coming off a win, but we know the things we need to work on. And it’s really about getting those things done week by week, because as the season starts to get closer to the end, you run out of time, so I think there’s an urgency to fix those things and get better at them.”

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It’s clear, after Seahawks quarterback Russell Wilson shredded the Patriots for 348 yards and three touchdowns with no interceptions, that the secondary needs to work on its coverage and its communication in the defensive backfield. The loss exposed what a good, well-coached team could do to the Patriots in a playoff game if they’re not prepared. It certainly did a better job exposing their weaknesses than it would have if the Patriots won.

There has been a lot of chatter in the fallout from the loss about the defense. McCourty seems to have been listening. He knows that they need to improve, and fast, if they want to be anything approaching a championship-caliber defense, or at least have a better balance between offense and defense that characterizes a Super Bowl-caliber team. And silencing the critics will all come down to what they do on the field.

“It’s simple, we’ve just got to play better,” said McCourty. “There’s nothing I can say to calm that or anything. We’ve just got to go out there and play better. … That’s what everyone in the locker room, everyone on the defense wants to do. There’s nothing to say, you’ve just got to go do it.”

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Matt Dolloff is a writer for CBSBostonSports.com. Any opinions expressed do not necessarily reflect that of CBS or 98.5 The Sports Hub. Have a news tip or comment for Matt? Follow him on Twitter @mattdolloff and email him at mdolloff@985thesportshub.com.