FOXBOROUGH, Mass. -- The New England Patriots and safety Duron Harmon have reached agreement on a four-year deal worth a maximum value of $20 million, sources tell ESPN. Harmon's agent later tweeted on the agreement.

ESPN 150 ranking: 50th

Grade: A-minus. When it comes to intangibles and leadership, Harmon is in a league-leading category. He's the type of player any championship team wants in its locker room. An example of this came at halftime of Super Bowl LI when Harmon was upbeat and telling teammates they had just put themselves in position to put together the greatest comeback in Super Bowl history. But all those words don't mean much if they aren't backed up on the field, and Harmon is a valuable No. 3 safety, a growing role in today's NFL that has defenses in sub packages 65-75 percent of the time. Harmon played 48.6 percent of the defensive snaps last season -- often in a center-field type role -- and also was part of multiple special-teams units. In free agency, he tested the market, which didn't produce a blockbuster offer that would have enticed him to depart, so he returns on a midlevel deal with financial upside.

What it means: The Patriots return their entire safety corps, led by starters Devin McCourty and Patrick Chung, and then with Harmon, Jordan Richards (2015 second-round pick) and Nate Ebner. From a team perspective, the Patriots couldn't have drawn it up much better than that.