INDIANAPOLIS — Free agent linebacker Preston Brown has a hint of Patriots envy.

Quite frankly, it’s hard to blame him.

The NFL’s reigning tackles leader has watched former Bills teammates stampede out of Buffalo and turn into stars with the Patriots. It wasn’t easy to process, but now that Brown has a similar opportunity on the open market, he can’t help but think about the possibility.

“It’s a little weird,” Brown said of his ex-teammates thriving for their AFC East rivals. “I’m not going to sit here and lie like, ‘Oh well.’ You’re happy for them, but you’re also like, ‘All right, every time somebody goes to the Patriots, they’re going to the Pro Bowl or the Super Bowl.’ It’s something you feel. A lot of guys left the last year, and it seemed like everybody who left us was going to the playoffs — (Rams wide receivers) Sammy Watkins and Robert Woods, (49ers receiver) Marquise Goodwin. Everybody who left had a good season. It’s definitely something you look at like wow, those guys are having success. But the Patriots, they definitely seem to get the best out of the Buffalo Bills.”

Brown, who had 144 tackles last season, fits an obvious offseason need for the Patriots. And Bill Belichick is familiar with the middle linebacker after a pre-draft workout at Louisville in 2014, when Brown was selected in the third round.

Now, it’s believed the Patriots are among the teams interested in Brown’s services, and his suitors’ curiosity could pique this week as the league converges upon Indianapolis for the scouting combine. The Bills are trying to keep him, and it’s Brown’s preference to stay if they hit his price.

There’s a lot to like about Brown, a locker room leader who never has missed a game in his four-year career and has called plays in the huddle. Given the Patriots’ injury woes last season at inside linebacker, Brown’s stability and durability would be desirable as they work to reinforce their front seven.

“I think I can definitely help the young guys they have,” Brown said. “They’ve got some good young talent at linebacker. They run pretty well. I know (David) Harris retired. A lot of young guys were playing well, (Kyle) Van Noy and (Elandon Roberts) played well. They definitely have some things they can work on like we all do, but I think I can help that defense get better. “

And Belichick clearly has enjoyed the chance to pluck away the Bills’ talent in the past two years. In 2016, wide receiver Chris Hogan transformed from a rotational player to one of Tom Brady’s favorite targets. Last season, cornerback Stephon Gilmore landed a five-year, $65 million contract and might have been the Patriots’ best defensive player in the playoffs. Running back Mike Gillislee finished the 2017 season on a down note, but he had four touchdowns in his first two games with the Pats.

“I just think the whole organization in New England does a great job of knowing what those players’ skills are and then utilizing them in that way,” Brown said. “They know Chris Hogan can run vertical, so they throw him vertical routes. They know Stephon can play zero-(safety), man-to-man coverage all day, and that’s what he does. . . . Those guys definitely played well when they were out there.”

Brown is in an interesting spot. He was a key member of a team that ended their 17-year playoff drought and understood, as a teammate and member of the community, how difficult it could be to see ex-Bills contribute for the perennial Super Bowl contenders. That’s why he was so conflicted to see Gilmore depart.

“I used to talk to him a lot during the free agency part to see what he was going to do,” Brown said. “Then all of a sudden, he signed with the Patriots, and I stopped talking to him a little bit. I definitely was excited for him. He was doing great. We saw him the first couple weeks, and all the Buffalo fans were a little happy that he was getting burnt sometimes. I was like, ‘Gilmore is going to be all right.’ He turned it around and went out there and had an amazing game in the Super Bowl. He was definitely one of the bright spots in that defense.”

Brown has immense respect for the Patriots, who have won 31 of the past 35 meetings with Buffalo. Just listen to a reason he gave for his career trajectory.

“I think one of the biggest reasons is you’ve got to play the Patriots twice a year,” Brown said. “That’s something you talk about in OTAs, minicamp. You’re talking about the Patriots and how you’ve got to defend them. Me being a middle linebacker, I’m guarding (Danny) Amendola and (Julian) Edelman all day in those option routes, and (Rob) Gronkowski. The extra (offseason) work I do here in Cincinnati with my dad, just working on those option routes, all those plays that I get throughout that game. I’ve got to make sure I can defend it. That helps me translate it because we know what we’re going to see with the Patriots.”

Now, Brown owes it to himself to maximize his opportunity, whether it’s in Buffalo, New England or elsewhere. If he can get $8 million annually, the Patriots likely won’t be key players for his services. But if that number dips — only seven 4-3 inside linebackers earn at least $5 million annually — it’d make plenty of sense for Belichick to pay another Bill.

Brown would happily listen.

“Anytime you can play for one of the best franchises in NFL history, it’s obviously going to be an option,” Brown said. “They definitely have great players. I met with the coaching staff coming out of college. I have some familiarity with those guys, and they definitely do a great job each and every year of continuing to win.”