By Matthew Geagan, CBS Boston

BOSTON (CBS) — The 2020 NFL season is over, with Tom Brady once again hoisting the Lombardi Trophy. While the majority of Patriots fans are happy for their team’s former quarterback, that should wear off quickly when attention turns back to their own team.

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Simply put, Bill Belichick and company have a lot of work to do in 2021 if they want to flirt with a return to glory. At this point, they’re going to have to do a lot of work just to get back to the playoffs. While the 2020 opt-outs are expected to return, which should provide a boost on the defensive side, there are some giant holes to plug all over the roster if New England wants to bounce back from a 7-9 campaign.

The most glaring hole remains at the quarterback position, with Jarrett Stidham all there is on the depth chart. But Belichick also needs to get to work rebuilding the defensive line, while also plugging in a few holes on the offensive line. It would also probably help to add a receiver or two for whichever quarterback is throwing the football next season.

With 22 players hitting free agency — including key players like David Andrews, Joe Thuney, James White and Lawrence Guy — it’s going to be a busy, busy offseason for the Pats. Here are some important dates to circle on your calendar:

Franchise Tag: Feb. 23-March 9

The Patriots hit Thuney with the franchise tag last offseason, paying him nearly $15 million in 2020. They have a number of players to hit with the tag this offseason, though it will again cost them a pretty penny. The deadline to franchise a player is March 9.

Legal Tampering Period: March 15-17

The best time of the year, when rumors and “unofficial contracts” take over everyone’s lives. Teams can chat with free agents in the 48 hours leading up to the start of free agency but cannot officially sign them. Most deals are worked out — and leaked — during this period.

Free Agency: March 17 at 4 p.m.

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Free agent contracts that we’ve already heard about can become official. If the Patriots haven’t already traded for a veteran quarterback at this point, they may be adding one to help boost their chances with other free agents. Chances are receivers aren’t going to want to come to a team with a giant question mark at the most important position on the field, so it will be important to have some modicum of clarity at quarterback at this point.

Restricted Free Agents Deadline: April 23

The Patriots have a pretty big name hitting restricted free agency this offseason in J.C. Jackson. The corner had a career year in the New England secondary with nine interceptions in 2020, so it will be interesting to see if any other team tries to pry him away from the Patriots. The Pats will likely toss a first-round tender on Jackson, so any team that tries to sign him away from New England would have to forfeit a first-round pick.

Jackson is an integral part of the defense, with 17 interceptions over his three-year career. With the likelihood that top corner Stephon Gilmore will be traded this offseason extremely high, chances are the Pats will want to do everything they can to hang on to Jackson.

Other teams have until April 23 to extend an offer sheet to Jackson and other RFAs. Any player’s original team has until April 28 to match that offer.

NFL Draft: April 29-May 1

Whoa boy this should be a fun one. The Patriots are projected to have 10 picks in the upcoming draft, including the No. 15 overall pick in the first round. They should be taking a quarterback at some point, and if they don’t have a veteran in the mix already, they may be trading some of their picks for an established QB. Either way, the Patriots need a quarterback of the future, and they will hopefully find one over this three-day stretch.

Here is a quick rundown of New England’s current selections:

1st round pick
2nd round pick
4th round pick
5th round pick
6th round pick
6th round pick (via Dallas)
7th round pick

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The Patriots will also likely get a third-round compensatory pick for that Brady guy, and a pair of fourth-round comp picks for Kyle Van Noy and Jamie Collins, both of whom left via free agency last offseason.