For many of the so-called experts, the Bulls are a tough team to figure out.

They lost shooting guard Ben Gordon -- their leading scorer the last four seasons -- via free agency but still have an impressive young roster.

Do they lose points for losing Gordon, or do they gain points because some of their young players have more experience and should be better?

Many observers believe the Bulls will improve on last season's 41 victories and contend for home-court advantage in the first round of the playoffs.

Here's a look at five things the Bulls must do for that to happen:

1. Play strong defense

The Bulls won half their games last season despite a defense that had more holes than a truckload of Swiss cheese. A large focus of training camp was shoring up the defense. For what it's worth, the Bulls held their opponents to a field-goal percentage of .403 in the preseason.

''We were No. 1 in defensive field-goal percentage,'' John Salmons said. ''I know preseason doesn't really mean anything, but it's a step.

''We feel like the only way we can accomplish what we want to accomplish is on the defensive end. That's the only way you can win games consistently. Scoring is gonna come and go. If we can be consistent on defense, we'll have a chance every night.''

One reason they have a chance to be better every night is that Salmons is replacing Gordon at shooting guard. Salmons is 5 inches taller and can defend a variety of players.

Another reason is point guard Derrick Rose will be better with a year's experience.

''We're better,'' Del Negro said of the defense. ''The trust factor takes time to build. The communication and talking and some of our rotations have gotten better, but now it's a matter of putting it in real games that matter and trusting your teammates, and trust takes awhile to build.

''I feel we're going in the right direction with it, and guys are putting in the effort. Usually, when you do that, good results happen.''

2. Make size matter

Ever since Eddy Curry was traded to the New York Knicks four years ago, the Bulls have been undersized and undermanned up front. No more.

With an improving Joakim Noah and Brad Miller, the Bulls have two effective centers and also have impressive depth at power forward with the addition of rookies Taj Gibson and James Johnson to go along with Tyrus Thomas.

The return of Luol Deng and the move of Salmons improve the size at those positions as well. Don't be surprised tonight to see Del Negro go with a front line of Noah, Miller and Thomas or Noah, Gibson and Thomas at times. Del Negro believes playing Thomas at small forward gives the Bulls a big advantage.

''We have to control the glass better, and when you have more size out there, more athleticism, if we do the right things, we can get out and run,'' Del Negro said. ''Against certain teams, you want to get out and attack them on the break. With Tyrus at the three, when he goes and attacks the glass, that's a bonus for us.''

3. Rose hits the pedal

As a rookie, Rose averaged 16.8 points despite often deferring to his teammates. He should be more aggressive this season, and that -- combined with the loss of Gordon -- could boost his scoring average into the low 20s.

Perhaps more encouraging is scoring was the farthest thing from Rose's mind Wednesday when asked if he'll boost his offensive averages.

''I haven't thought about numbers,'' he said. ''If anything, I want my assists to go up. There's a lot of good scorers on this team, and they're gonna have to do their part.''

He averaged 6.3 assists last season.

4. Dig deep

During the playoffs last season, Del Negro went with a seven-man rotation most games out of necessity. Depth wasn't the Bulls' strongest suit last season.

But with the drafting of Gibson and Johnson, the return of Deng and the signing of Jannero Pargo, the Bulls have impressive depth -- at least on paper.

They'll start the season with only 11 healthy bodies, so an untimely injury -- or even ineffectiveness by a player or two -- could eliminate that perceived depth advantage.

5. Get a good health plan

Like most teams, the Bulls' optimism can be abruptly shattered by an injury to a key player. Injuries could have a negative impact on all of the aforementioned areas and turn strengths into weaknesses.

Of special concern is the ankle injury that hampered Rose much of the preseason. He'll start the season at less than 100 percent, and that's why Del Negro will closely monitor his minutes.

''My caution is because he hasn't practiced a lot and hasn't played a lot, and if I go and play him a bunch and all of a sudden his ankle swells up, he's out two or three weeks instead of taking it smart,'' he said. ''We're trying to look at the big picture.''

TONIGHT

SPURS AT Bulls

The facts: 7, TNT, 890-AM.

The story line: After eight preseason games and four consecutive days of practice this week, the Bulls finally are set to open the regular season. The radio broadcast shifts to WLS-AM (890) because WMVP-AM (1000) will be carrying Game 2 of the World Series.

John Jackson