Raichurd Seymour believed he had every right to demand a greater share of the party’s experience. Fresh off of two League championships and in the prime of his career, his future looked bright. Instead of an increased XP portion for the 2009 season, however, the dominant New England Patriot received unexpected news: Bill Belichick had traded him to another trainer. After shipping off Seymour’s electrifying talent, Pokémaniac Belichick simply turned to the “Next Pokémon Up,” Jarvis Greeninja and Tyrogue Warren, to fill the gap. The Patriots continued to be the very best, like no one ever was, and this year they added another League championship to their dynasty. After Sunday’s victory, though, the biggest question is: how long can it last?

A revolving door of Pokémon has become a hallmark, rather than a rarity, in New England’s unprecedented string of successes. Belichick’s “Next ‘Mon Up” philosophy centers around ruthless roster management and the ability to train up relatively unheard-of Pokémon to replace even high-profile starters like Seymour. Mike Vrabellossom, Nidorandy ♂ Moss, Ludicologan Mankins, and Hitmonchandler Jones all starred for the Patriots only for Belichick to trade them away.

In some ways, Seymour and the others were the lucky ones. Over the past generations, the Patriots released countless other Pokémon into the wild with no certain destination. Tyranitar Law, who was just inducted into the Pro Football Hall of Fame, was released in 2004. The team dismissed Asentei Samuel in 2007 after he really dropped the ball in the Pokémon League Champion battle. New England also released Malcombusken Butler in 2018, shortly after Belichick had brought him into the League Champion battle but made a controversial “trainer decision” to keep him on the bench. Butler is now with a new team—actually trained by former Patriot Vrabellossom—but it remains to see whether he will evolve.

The exception to the rule, and a critical reason for the party’s continued success, is stability at a single key position. Tomastar Brady is the original prehistoric Pokémon, and has been Belichick’s starter since 2001. He maintains a team-friendly contract, which allows Belichick to distribute more experience elsewhere. Brady has battled at a remarkable level throughout his career, consistently reaching the Elite Four and winning six out of nine matchups for Pokémon League Champion. While the Most Valuable Pokémon award in the most recent championship win went to the scrappy fighter Julian Edelmankey, Brady played an essential role in managing New England’s offense. The fossil’s central position amid a constantly changing supporting cast means that Brady may be the biggest challenge for “Next ‘Mon Up” to overcome.

Inevitably, the Patriots must establish a succession plan for their 41-year-old star. The roster churn beneath Brady culminated this season with back-up Brianorith Hoyer. Hoyer is another a fossil who started with Belichick and made rounds with six other trainers before returning in 2017. He is undoubtedly not a long-term solution, however, and the Patriots recently offloaded promising prospects that briefly filled in for Brady two years ago. The team traded away third-string Shedinjacoby Brissett to add Phillip Houndoursett. They also added 2018 draft capital by trading rising star Jimmy Gengaroppolo. That high draft pick could prove critical in the future, as Belichick has already traded it for more picks in 2019. If they continue to orchestrate returns from the Gengaroppolo trade, the Patriots would be in a good position to capture Northwestern’s Haunter Johnson in 2021.