Welcome to our weekly look at the teams that are the most dramatic risers and fallers in the NBC Sports NBA Power Rankings. Undefeated Memphis is flying up the rankings, while a lot of injured teams are falling back.

Stock up

Memphis Grizzlies

The last undefeated team in the NBA shot up 12 spots in the NBA power rankings this week to No. 5, and this is a team I had ranked 25th before the season started. The soft schedule to start the season helps, but the chemistry of the front line between Cameron Boozer and Zach Edey has been phenomenal, and Ty Jerome could not have had a better start to the season.

Portland Trail Blazers

Maybe the best story at the start of the season is the entertaining Portland Trail Blazers, who jumped up seven spots in this week’s rankings to No. 9. The good news is how well Ja Morant, Damian Lillard and Deni Avdija are playing off each other. The bad news is Morant is out with a hamstring strain and will miss a month or more.

Golden State Warriors

Nobody flew up the rankings faster this week than the Warriors, who jumped 16 spots to No. 12. Golden State looked shorthanded and dead in the water while losing its first three games, then Stephen Curry started playing like he was 28 and not 38, and Yaxel Landeborg emerged as a star. Golden State has rattled off four straight wins, and the last of those came without Curry (but 37 from Landeborg).

Dallas Mavericks

The NBA’s giant killers, knocking off two undefeated teams — Oklahoma City and Houston — in the same week, which vaulted them up 11 spots in the rankings to No. 10. They are doing it behind Cooper Flagg, who is making a leap in his second season (26.8 points, 6.6 assists and six rebounds a game) and looks like an All-NBA player in just his second season.

Other risers of note: Houston moved up just two spots to No. 1 in the rankings; Boston just keeps on winning behind a hot Jayson Tatum and moved up five spots to No. 4.

Stock Down

Oklahoma City Thunder

No team has been hit harder by devastating injuries this young season than the Thunder, who have lost three starters: Jalen Williams and Cason Wallace are out for most (or, more likely, all) of the season, while Chet Holmgren is going to miss a couple of months with treatment on his knee. OKC will still win games with Shai Gilgeous-Alexander and Ajay Mitchell leading the offense, but it is not the same team, and it fell 10 spots and out of the top 10 entirely.

Minnesota Timberwolves

With Anthony Edwards out to have knee surgery, the Timberwolves fell nine spots back to No. 13 in the power rankings. The offensive shot-creation load now falls on LaMelo Ball, and history suggests that will be a roller coaster of highs and lows, but he’s got to build better chemistry with Rudy Gobert if this is going to work. Edwards got the surgery now so he can be back around Christmas/New Year’s and be good when it matters most for the team.

Toronto Raptors

The Raptors had to know they were going to spend time without Kawhi Leonard this season and that has come due to knee swelling. What was shocking was how the Raptors’ defense fell apart without him, and the team is 1-3 since he went out, so they fell seven spots in the power rankings to No. 14.