NBA power rankings 2012: Bulls fall to No. 12 after disappointing week

The Chicago Bulls fell to No. 12 and the Memphis Grizzlies moved into the top spot in this week's SB Nation NBA Power Rankings.

Chicago played four games this past week. They defeated the Phoenix Suns in overtime but lost to everyone else, including the Boston Celtics, Los Angeles Clippers and Portland Trail Blazers. Most alarming in that stretch is the Bulls lack of defense, as they allowed more than 100 points in all four games.

The Bulls may be simply looking to tread water and stay around .500 until Derrick Rose can return midseason and get the team peaking as they head into the playoffs. But a porous defense won't keep the Bulls afloat. Seth Rosenthal, who compiled the power rankings, wrote the following about the Bulls' disappointing past week.

The defense I called "terrifying" last week has fallen off sharply since around the time the Bulls' annual circus trip began, pretty much right after last week's rankings. So, uh, let me just make it clear that I also find cold weather and not having an endless supply of delicious cheeses terrifying.

The Bulls face the Houston Rockets and Milwaukee Bucks this week, both on the road.

The 8-1 Memphis Grizzlies are at the top of the rankings after sweeping their four-game schedule last week, including double-digit wins against the Thunder, Heat and Knicks. They carry an eight-game win streak into their Monday night contest with the Denver Nuggets.

For complete NBA power rankings, click here.