The 2025-26 NBA regular season is winding down, which means that the postseason is right around the corner.Will the Oklahoma City Thunder win another NBA championship? How far can the surprise Detroit Pistons make it? What about Boston Celtics with superstar Jayson Tatums shockingly fast return from an Achilles injury?Well find out the answers to those questions in the coming weeks, but the end of the regular season also means we get to see how those preseason over/unders ended up.Which teams outperformed expectations and which underperformed?Heres a list of the NBA teams have clinched their preseason over or under at BetMGM sportsbooks, along with the six teams still undecided with a few games remaining.Still undeterminedDenver Nuggets: 53.5 New York Knicks: 53.5 Houston Rockets: 52.5Minnesota Timberwolves: 49.5Atlanta Hawks: 47.5Philadelphia 76ers: 43.5 Teams that have clinched their overOklahoma City Thunder: 62.5Detroit Pistons: 46.5 Los Angeles Lakers: 46.5San Antonio Spurs: 44.5 Boston Celtics: 41.5 Toronto Raptors: 39.5Miami Heat: 37.5Portland Trail Blazers: 35.5 Phoenix Suns: 30.5Charlotte Hornets: 27.5Brooklyn Nets: 19.5Utah Jazz: 18.5Teams that have clinched their underCleveland Cavaliers: 56.5Orlando Magic: 51.5 Los Angeles Clippers: 49.5 Golden State Warriors: 47.5Milwaukee Bucks 43.5 Dallas Mavericks: 41.5 Memphis Grizzlies: 39.5Indiana Pacers: 39.5 Chicago Bulls: 33.5 Sacramento Kings: 32.5 New Orleans Pelicans: 30.5 Washington Wizards: 20.5