The New England Patriots have lost some key pieces from their Super Bowl LIII-winning team, but Pro Football Focus still ranks Bill Belichick's roster as the best in the NFL entering the 2019 season.

Here's a look at PFF's top 10 rosters with training camps less than a month away. 

The Patriots did lose some key pieces in free agency, most notably starting left tackle Trent Brown and defensive end Trey Flowers. Future Hall of Fame tight end Rob Gronkowski also retired, and veteran Ben Watson and Matt LaCosse were brought in to help fill the void at the position. 

New England, however, still has its most important player in quarterback Tom Brady, who shows few, if any, signs of slowing down after a strong 2018 season. The Patriots also have an extremely deep group of running backs, the league's most clutch wide receiver in Julian Edelman and a very good offensive line. The team's defense, which held the Los Angeles Rams to a record-low three points in Super Bowl LIII, is bringing back most of its top players as well.

Oh, and Belichick is the best head coach in NFL history.

Let's be clear -- the Patriots by no means have a perfect roster. There are genuine question marks, particularly at wide receiver and tight end. But it's not exactly a surprise PFF ranked the Patriots' roster No. 1 in the league, especially when Brady remains at the helm.

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