The thing is, they have already won games without Rose. Just look at last year.
Rose suffered his ACL tear in Round 1 of the playoffs against the Philadelphia 76ers. Losing Rose at such an inopportune time combined with the potential severity of the injury shocked the Bulls visibly, and they lost the series in six games. Credit belongs to Philadelphia, an under-seeded team that took advantage of the shell-shocked Bulls.
But don't expect the Bulls to be such easy prey next season, even without Rose. In the regular season last year, Rose missed 27 games—in which the Bulls went 18-9. And better yet for head coach Tom Thibodeau, the Bulls squad this season—minus Rose, of course—is better than the Rose-less team of last year.
Certainly, the Bulls will miss the contributions of Omer Asik (signed with Houston), Ronnie Brewer (signed with New York) and Kyle Korver (traded to Atlanta). But the new additions, combined with excellent play from a few returners, can improve the Bulls' depth beyond last year's.
Starting guard Rip Hamilton missed 38 games last season, and if he can stay consistently healthy, he'll make a bigger impact than he did last season. Second-year guard Jimmy Butler is expected to have a larger role this year, after averaging 20.6 points and 6.5 rebounds in the 2012 Summer League.
Chicago also added some talented bench players such as Nate Robinson, Marco Belinelli and rookie Marquis Teague. Veteran guard Kirk Hinrich will likely serve as the starting point until Rose returns. With his all-around skill set and tough defense he's a dream come true for coach Thibodeau.
Another reason the Bulls can surprise the NBA without Rose: I expect far bigger seasons for both Carlos Boozer and Luol Deng in Rose's absence.
In the 19 games that the Bulls played between January and March, Boozer thrived—he averaged 16.8 points and shot 60.9 percent from the field. In the eight games in April that Chicago played without Rose, he struggled, and he brought those non-Rose stats down to 15.3 points and 55.8 percent shooting. Both are still higher than the 15.0 points and 53.5 percent shooting he had for the season as a whole.
Bet on Boozer to continue his higher production in Rose's absence. Not only will the Bulls need him to score (thus getting him the ball more) but he'll also have more room to operate. Rose is an excellent passer, but he's also a slasher scorer and his primary go-to weapon is to attack the basket. Whenever he'd drive to the lane, he'd bring a defender (sometimes multiple) down into the paint with him.
Without Rose clogging the paint, Boozer could return to his Utah Jazz form. His best seasons were in Utah, when he played with a more prototype point guard in Deron Williams. Rose's replacement, Kirk Hinrich, is no Williams for sure, but he's a more traditional point guard. He won't attack the paint like Rose, and the Bulls will likely slow the pace down with Hinrich at the helm. This means more space and more touches for Boozer.
As for Deng, he told Ian Whittell of ESPN that he will likely not need surgery on his wrist and expects to be ready to go when the season starts. While Deng may not have the offensive potential that Boozer has (Boozer's career high was 21.1 points per game in 2007-08, compared to Deng's high of 18.8 in 2006-07), he will still be a big key to the Bulls offense. As long as he can be more effective than he was last season (when he averaged 15.3 points but shot just 41.2 percent from the field).
The biggest reason to expect an unexpected season from the Bulls is Thibodeau. Since signing with the team, he's been one of the NBA's most efficient coaches. Chicago has been at the top of the defensive rankings year after year, and that will continue without Rose. Thibodeau demands (and gets) defensive excellence from his players, and as long as he is coaching the Bulls, they’ll be in the fight for a playoff spot.
Thibodeau kept the Bulls afloat without Rose last year, and they only got better this year. They won't be title contenders without their star, but the Bulls are still in the playoff hunt and can challenge for the Central Division crown.