Obviously that will change soon, but it’s a noteworthy development. Jeff Howe had an interesting theory regarding these moves. “The Patriots could put Nick Folk on the practice squad and make him eligible for the game-day 55-man roster for a couple weeks to preserve a spot on the 53, all while evaluating who's available, or then promoting him back to the 53”, Howe tweeted. This comes from the new rule that teams can promote two players to the active roster for game day, making a 48-man active roster (though one of the extra spot to get to 55 would have to be an OL).
It’s also entirely possible they simply bring Folk back to the active roster, possibly after Week 1 when veteran salaries no longer become guaranteed.