NBA power rankings 2012: Heat fall to sixth in latest SB Nation rankings

Despite losing just once last week and a 5-2 record to start the 2012-13 season, the Miami Heat fell to sixth in the latest SB Nation power rankings.

Miami notched wins over the Phoenix Suns, Brooklyn Nets and Atlanta Hawks last week, before losing to the Memphis Grizzles on Sunday, 104-86.

Seth Rosenthal still questions Miami's disappearing defense through the Heat's first seven games of this season.

The Grizzlies were an extreme and unstoppable force in that game on Sunday, but even still, we got a look at how grim things can be for the Heat right now if that murderous offense doesn't feel like murdering on a given night against even halfway-decent opposition. One can assume the defense will wake up, but it's still very much asleep. They're unusually beatable at the moment.

Even though the Heat are 5-2, Miami's defense has allowed 98.9 points per game -- 22nd overall in the NBA.

Poor rebounding could be partially to blame, as the Heat are averaging just 39.6 rebounds per game, 25th in the league. No matter the cause, Miami's defense is a cause for concern this year, but it's still very early in the season.

Miami's defense will be put to the test this upcoming week, with four road games on the schedule. Miami is set to take on the Rockets, Clippers, Nuggets and Suns before returning home next week.