Progress of Patriots' D will be tested without Dont'a Hightower

Hightower done for season (0:53)

Adam Schefter joins SportsCenter to discuss Patriots linebacker Dont'a Hightower's season-ending pectoral injury. (0:53)

FOXBOROUGH, Mass. -- The New England Patriots' defense has made notable strides in recent weeks and the return of linebacker Dont’a Hightower one of the reasons.

But now, as the NFL Network first reported, the defense will likely have to keep things going without Hightower all season because of a torn pectoral muscle.

It's a tough blow to a unit that has seemed to find itself last week in a victory over the Atlanta Falcons.

“Honestly, it’s just building chemistry,” linebacker Kyle Van Noy said in a Tuesday interview on SiriusXM NFL Radio, when asked what has sparked better defensive play in recent weeks. “A lot of people kind of lost sight that we have a bunch of new guys, and a lot of young guys as well, and we traded for some new guys at positions that have been a cornerstone with guys like Rob Ninkovich.

“When we have a plan like that with new guys, we have to get them all on the same page. It took some time. Now we’re slowly figuring out how to play with each other and getting better and better each week.”

Hightower’s calming presence, which was missed when he was sidelined with a knee injury in the second and third weeks of the season, had been a big part of it. He is often seen before the snap communicating to teammates. His knowledge of the scheme, which is a result of being in his sixth year in the system, makes him a go-to-guy when he is on the field.

As has been the case in past years when Hightower has been sidelined, there is no one-for-one replacement for him, but Van Noy’s role in the defense will take on added importance. He’s played 95.5 percent of the defensive snaps this season, the only linebacker who has stayed on the field in all packages, including the dime.

This also could mean veteran David Harris, who played a season-high 19 defensive snaps in Sunday’s victory over the Falcons, will become more of a regular part of the linebacker rotation. One thing that stood out with Harris on Sunday night: He remains a sound tackler when playing downhill.

The 6-foot-2, 250-pound Harris had been working behind Elandon Roberts (6-foot, 235), but with Roberts managing an ankle injury that knocked him out of Sunday’s game, it created more of an opportunity for the 33-year-old Harris. Coaches seemed to like what they saw.

“David works hard and is very well prepared and did all of the right things that we would want him to do from an assignment standpoint -- handled the communication in the front well,” coach Bill Belichick said earlier this week. “We’ll see if we can build on it. We’ve got a lot of good play from a number of guys and he’s certainly part of that group.”

Marquis Flowers (6-3, 250) and Trevor Reilly (6-5, 240), whose primary contributions come on special teams, round out the linebacker depth chart, with Shea McClellin's expected return from injured reserve Nov. 12 against Denver adding another personnel option.

Hightower's injury puts more stress on defensive coordinator Matt Patricia, who has been tasked with putting pieces together on the fly. He’ll need even more from Van Noy, who was acquired in a trade Oct. 25, 2016, meaning he’s now been in the system for one full year.

“You come in and you don’t want to be that weak link that messes up what’s been going on," Van Noy said in his SiriusXM NFL Radio interview. “This defense is not easy to learn and I had to learn it in two weeks [last year] and then I started playing. I didn’t want to be the problem; I have to hold myself to a higher standard because I don’t want the guy next to me not to trust in me. When you have that, and have a collective group that has bought into the same thing of winning and not letting the person down next to you, it causes a great chain reaction to a brotherhood that is sustained here and everybody wants to be a part of it because we win games.”

That will be tested in without Hightower.