​”You’re in, then you’re out. You’re up, then you’re down.”Some will look at those words and think they’re lyrics from Katy Perry’s hit song, “Hot N Cold.” Others will see those same words and believe they’re an ode to fantasy football defenses.Whatever your view, just know that we’re talking about those pesky D/ST’s that keep you up at night. After all, nothing in fantasy football runs more hot and cold than a D/ST on a week-to-week basis.A long offseason has finally given way to some meaningful football, marking the return of fantasy start-and-sit decisions. We’re all a little out of practice and operating with no real data during the early stages of the season, so this will be a learning experience for all of us – together.Additions and subtractions through free agency, trades and the draft shook up the league’s landscape. Now we’ll try to make sense of it to put you in the best position for fantasy success.Now how about we start the season on the right foot? Or left, if you prefer. Anyway, here’s a look at your fantasy D/ST rankings for Week 1 of the 2026 NFL season.Fantasy football D/STs rankings Week 1Jacksonville Jaguars (vs. Cleveland Browns)Los Angeles Chargers (vs. Arizona Cardinals)Philadelphia Eagles (vs. Washington Commanders)Seattle Seahawks (vs. New England Patriots)Denver Broncos (at Kansas City Chiefs)Houston Texans (vs. Buffalo Bills)New York Jets (at Tennessee Titans)Los Angeles Rams (vs. San Francisco 49ers in Melbourne, Australia)Baltimore Ravens (at Indianapolis Colts)Pittsburgh Steelers (vs. Atlanta Falcons)Minnesota Vikings (vs. Green Bay Packers)Buffalo Bills (at Houston Texans)Detroit Lions (vs. New Orleans Saints)Dallas Cowboys (at New York Giants)Tennessee Titans (vs. New York Jets)Chicago Bears (at Carolina Panthers)Fantasy football start ’em, sit ’ems, Week 1Looking for more fantasy football advice? USA TODAY Sports has you covered:→ Need an edge under center? Here are the best quarterback options to start and to sit in Week 1.→ A good running back makes all the difference. A bad running back can cost you. Here’s who to start and who to sit in Week 1.→ Tight ends can be the perfect X-factor for any fantasy team. Here’s who you should start and sit in Week 1.→ The wide receiver position is one of the deepest each season. Set yourself up for success in Week 1 with start ’em, sit ’em advice for wideouts.This article originally appeared on USA TODAY: Week 1 fantasy football defense rankings: Best D/STs to start