BOSTON (CBS) — Bill Belichick was football’s biggest spender once the tampering window for free agency kicked off on Monday, dishing out deals left and right to overhaul the Patriots’ roster.

While the desire to improve upon last year’s 7-9 record is obvious on its face, NFL super agent Drew Rosenhaus — who negotiated the Jonnu Smith, Davon Godchaux, Jalen Mills and Trent Brown deals directly with Belichick — provided some rare insight into the mind of the Patriots boss during this frenzied period.

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“They had the money out there, and they were hungry. I just got the sense that Coach Belichick was hungry,” Rosenhaus told Peter King on his podcast. “I got the feeling that last year didn’t sit very well with them. I got the feeling they weren’t content missing the playoffs. And I got the sense that they were going to do a lot to improve their football team. And they were able to do things that other teams couldn’t do. And one thing about Belichick, I mean besides being a great coach, he’s also I think an outstanding talent evaluator and a great NFL executive. So I think it’s scary to give an outstanding coach like that tons of cap room that most teams don’t have. And I think the Patriots are going to be a very dangerous team this year.”

With the salary cap dropping this year, not as many teams were positioned to go crazy with free-agent additions. The Patriots — with a tremendous amount of money coming off their books — were not one of those teams. Rosenhaus said this was an advantage for Belichick, who never has trouble finding ways to gain an edge.

“They had an advantage this year that most teams didn’t have. They had the room, they have a great owner in Robert Kraft. He’s got cash. They’ve always been a team that’s been able to get deals done and been aggressive when they’ve wanted to be, and just … From my standpoint, they took advantage of an edge that they had,” Rosenhaus said. “I think we all agree that Belichick is very good at taking advantage of opportunities, and he did this year. He knew there were a lot of teams that didn’t have cap room and wouldn’t have the ability to go out and add great football players. And he did the exact opposite; he went and did that. He went and improved his football team by leaps and bounds. I think everybody would agree this roster is incredibly improved from the one that they ended the season with.”

Rosenhaus shared that he enjoys negotiating with Belichick, because he’s the decision-maker for the Patriots.

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“I like dealing with decision-makers. You know, a lot of the teams you deal with team negotiators, and they’re not the decision-makers. And that’s tough, because you can’t make the deal with them. What I really like about dealing with Bill Belichick above everything else is the fact that he is the decision-maker, from my estimation. And I like that,” Rosenhaus shared. “I like the ability, if you agree with him, you get a deal done. You don’t have to go back to another person, and that’s great.”

While most people never get to take part in such discussions with Belichick, Rosenhaus — who’s been dealing with Belichick since the Cleveland Browns days in the ’90s — said the negotiations can be more pleasant than most people might assume.

“Excellent. Kind of cuts to the chase. You’re obviously dealing with a future Hall of Famer and probably the greatest coach in the history of the NFL, so you have a lot of reverence for him,” Rosenhaus told King. “But he’s certainly respectful, and I think he’s a misunderstood personality. Anybody that has gotten to know him as well as I have I think would agree with me that he can be very engaging and very likable. So my dealings with him are always very positive.”

Rosenhaus said that 12 p.m. on Monday was “really hectic” and “a wild scene,” but the Patriots’ course of action seemed to just be a case of a team wanting to improve quickly.

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“The Patriots had cap room and they were aggressive and they took advantage of that,” Rosenhaus said. “Really their wealth of cap room, they really took advantage of that.” Staff