(h/t to reader James Kahn for the idea)
The Patriots had three cornerstone defenders of their Super Bowl team depart in free agency. Nose tackle Vince Wilfork and starting cornerbacks Darrelle Revis and Brandon Browner are all on new teams for the 2015 season. New England extended offers to each player, but remained unwilling to negotiate or enter a bidding war. It's a part of their plan.
All three players will be 30 or older once the season starts (Wilfork, 34; Browner, 31; Revis, 30) and New England has a history of moving away from aging veterans. This isn't to say that the Patriots don't utilize players over the age of 30, but instead that they are always ready to move away if the price tag gets too great.
When the Patriots moved away from defensive lineman Richard Seymour in 2009, it was a landmark moment in Bill Belichick's tenure as head of the New England front office. Seymour was one of the best defensive linemen in the league and he was only 29 years old- turning 30 in October. Belichick flipped Seymour to the Raiders for a future 1st round pick, which turned into Nate Solder.
Seymour played four more seasons in Oakland, including a record setting 2-year, $15 million extension for the 2011 and 2012 seasons. He was still a quality starter and didn't see much of a drop off in production from his final years with the Patriots- but the issue was with the price tag. Seymour was no longer the best defensive lineman in the league, and that record setting cost was too much for the value he returned on the field.
Since 2009, there have been multiple veterans who have departed for new teams, only to see their production fall off.
2009: OLB Mike Vrabel, 34, traded to the Chiefs along with Matt Cassel for the 34th overall pick in the draft. In the two seasons prior to the trade, Vrabel combined for 73 tackles, 16 sacks, and 62 stops. In the two seasons after the trade, Vrabel combined for 79 tackles, 2 sacks, and 50 stops. Vrabel was a leader, but he was not the same explosive player as before.
2010: DL Jarvis Green, 31, signed a 4-year $20 million contract with the Broncos. In the two seasons prior to departure, Green combined for 38 tackles, 3 sacks, and 32 stops. He was released prior to the start of the 2010 season, having suited up for zero games.
2010: TE Ben Watson, 30, signed a 3-year deal with the Browns. In the two seasons prior to departure, Watson combined for 52 receptions, 616 yards, and 7 touchdowns. He picked up 68 receptions, 765 yards, and 3 touchdowns in his first season with Cleveland. Watson outproduced his time with the Patriots, but the addition of Rob Gronkowski and Aaron Hernandez happened in the same year as his departure.
2010: WR Randy Moss, 33, traded away in the middle of the season, spending the year with a total of three teams. In the two seasons prior to departure, Moss collected 152 receptions, 2,272 yards, and 24 touchdowns (including one season with Cassel at quarterback). Moss was out of football in 2011.
2011 was a lock-out year, which leads to a major gap in time.
2012: C Dan Koppen, 33, the long time center moved to the Broncos after spending his 2011 season injured. Koppen started 12 games for the Broncos in 2012 and was out of football in 2013 after tearing his ACL.
2013: WR Wes Welker, 32, signed a contract with the Broncos (the third one?!). In the two seasons prior to departure, Welker collected 240 receptions, 2,923 yards, and 15 touchdowns. In his two seasons with the Broncos, he has 92 receptions, 1,242 yards, and 12 touchdowns. He's likely out of football due to injury concerns.
2014: OG Logan Mankins, 32, traded to the Buccaneers for the 2nd pick of the 4th round in the 2015 NFL Draft. Mankins started 26 games over the prior two seasons with the Patriots, grading out extremely well by Pro Football Focus' metrics. In his first season with Tampa Bay, his grade was roughly a third of his 2013 production as his lateral movement continues to decline. He also carries a large price tag.
When the Patriots move on from a veteran, it's because they're either about to fall off a cliff in production, or they're just not able to sustain their price tag. Players like Seymour and Mankins were still productive after leaving the Patriots, but they commanded top of the market contracts for slightly above average production. Receivers like Welker and Moss vanished after leaving New England.
Ben Watson is the only player over 30 to both meet his price tag and thrive outside of the New England system. He was the focal point of the Browns offense, collecting 154 receptions in three seasons versus the 167 receptions he picked up in six seasons with the Patriots.
So while Wilfork, Revis, and Browner are all joining new clubs, it's clear that the Patriots have a modus operandi that has a long line of success. Revis is still a great cornerback, but they aren't expecting him to match his play on the with the top of the market price tag for more than a season or two. Wilfork might have a successful year in Houston, but a fall-off in output is expected.
Browner's departure could be a mix of both- an expected cliff or a price tag- but could honestly just be a mismatch in skill set and expected defensive scheme. His contract value was fairly reasonable and didn't extend too far into his 30s, which is why scheme must be considered as an important factor.
The Patriots have a plan that they will continue to follow. Dan Connolly, 33 on September 2nd, remains a free agent. The contingency plans for Sebastian Vollmer, Rob Ninkovich, and Jerod Mayo are already in place. New England will continue to move on from players at just the right time.