The Miami Heat come to Chicago tonight to take on the NBA-leading Bulls. At 40-16, coach Spoelstra’s Heat currently sit three games behind coach Tom Thibodeau’s guys for the top seed in the Eastern Conference.

The Bulls, with a record of 44-14, have only 8 games remaining in the 2011-12 shortened schedule. And the Heat have only 10 games left. Neither side has any real worry about falling to the 3^rd spot in the East. So what accounts for the air of uncertainty surrounding these elite teams so late in the regular season?

The Heat’s team defense has slipped at the most important time of year, and as a result the South Florida Superteam has gone a pedestrian 5-5 over their last ten contests. In these games, Miami has allowed 47.3 percent shooting from their opponents compared to their overall season average of 43.2 percent. On Tuesday night in Miami, the Heat allowed the Boston Celtics to shoot 60.6 percent from the field in a 115-107 loss. This FG percentage was the best shooting of any opponent that Miami has allowed since the formation of the Big 3 at the beginning of last season.

The Bulls (6-4 over the last ten ballgames) have their own concerns as of late. Their team leader and 2011 NBA MVP PG Derrick Rose is hurt again and listed as questionable for tonight’s 48. Rose suffered a sprained right ankle in Sunday’s loss at New York and missed the rematch victory on Tuesday night in ChiTown. This comes after the 4^th-year superstar missed 12 straight games with a strained right groin from March 14^th to April 5th. Rose has missed 23 games this year, however the rest of the roster has picked up the slack and gone 16-7 in his absence.

The Heat bested the Bulls in Miami on January 29^th, 97-93. LeBron had 35 points, 11 boards and 5 dimes in the hard-fought ‘W’. On March 14^th in Chicago, the Bulls held off the Heat 106-102 even though LeBron had 35 and Chicago-native Dwyane Wade put up 36, and Rose didn’t play. The deep and versatile Chicago squad did have six players in double figures led by John Lucas III with 24.

This evening’s matchup will be the third of four head-to-heads for these two Eastern Conference Title favorites. Clinching the number one seed in the East and earning home-court advantage in the playoffs would be a tremendous advantage to these power teams as they are both monsters at home (Miami is 24-4 and Chicago is 23-6).

Tune in to TNT tonight at 8:00 PM ET to see who gets a leg up when the Chicago Bulls host the Miami Heat.