(Bruce Ely/Associated Press)

It hasn’t been a banner season for the NBA’s Eastern Conference. The Brooklyn Nets look old, the New York Knicks appear to be imploding and even teams that looked ready to take the next step (the Cleveland Cavaliers and Detroit Pistons) have struggled mightily. But the conference’s rock bottom seemingly came when the Chicago Bulls announced Monday that superstar guard Derrick Rose would miss the rest of the season after yet another knee surgery.

The Bulls, picked by many as the East’s best chance to end the Miami Heat’s three-year run as conference champions, find themselves stuck in the NBA’s version of “Groundhog Day.” They once again must decipher who they are without their former No. 1 overall pick.

Last season, the Bulls proved themselves an adept team without Rose. They won 45 games and beat the Nets in their first-round playoff series. Coach Tom Thibodeau says repeating last season’s success sans Rose will take a group effort.

‘‘We know you don’t replace someone like Derrick,” Thibodeau told the Chicago Sun Times this week. “There’s no one can step in and say you’re going to do what Derrick does. It doesn’t work like that. So for us, the way we did it in the past, we had to do it collectively.’’

If they could succeed last year, then why couldn’t they do the same again in a weaker Eastern Conference?

“Even more depressing than Rose limping to the bench the other night in Portland, is coming grudgingly to the realization that all those carefully laid plans, such as drafting Luol Deng and Joakim Noah and Taj Gibson and Jimmy Butler, and reacquiring Kirk Hinrich and signing Mike Dunleavy probably mean so little now, because an ensemble cast only works in the NBA when it surrounds a star, and Rose has been that star,” ESPN columnist Michael Wilbon wrote on Tuesday.

There are a couple of things working against the Bulls this season. The first being the lack of a natural scorer to step in to fill the void left by Rose. Nate Robinson took up the scoring reins for Chicago last season, averaging 13.1 points in 82 games (good for third on the team behind Deng and Carlos Boozer). But Robinson signed with the Nuggets in the offseason, leaving the Bulls looking for someone to fill a similar role this year.

Also working against the Bulls is Deng’s contract situation. The veteran forward is in the final season of his six-year, $71 million contract, which makes him attractive trade bait. While trade rumors swirl around him, Deng says he isn’t worried about what’s next.

“It’s unfortunate we’re going through what we’re going through but it is what it is,” Deng told ESPN.com. “You can’t worry about that as a player.”

But Kelly Dwyer of Yahoo’s Ball Don’t Lie says it’s much too soon to write off the Bulls, problems and all.

“This year’s team is ill-suited to play without Rose, but that doesn’t mean they can’t still make the playoffs in a miserable Eastern Conference,” Dwyer wrote. “Even after that four-game streak, the Bulls are still stuck at fifth in the East – between the bloody Bobcats and above Washington freakin’ Wizards.”

While the Bulls scramble to find their way, the East is left to figure out who could step up to take Chicago’s spot as a contender and possible Heat-slayer.

Washington Post columnist Mike Wise took to Twitter on Monday to put Rose’s torn meniscus in his right knee in perspective.

“Absolute killer. Man, I really thought Bulls as a healthy team could wear down Miami. Now Indiana and OKC are only hope,” he wrote.

The Pacers would seem to be an obvious choice. A spectacular 14-1 start has Indiana sitting atop the East, two games ahead of LeBron James and the Heat.

The emergence of Paul George, who averaged 19.2 points in the postseason and helped push the Heat to seven games in the Eastern Conference finals, continues to spark the Pacers this year. He’s increased his average this season to 23.7 points and the Pacers won their first nine games.

Atlanta was Indiana’s first-round victim last season, which led the Hawks to do some serious retooling in the offseason. The Hawks parted ways with Josh Smith (who signed with Detroit) and signed Paul Millsap to run alongside Al Horford and Jeff Teague. The trio has done well this season, averaging 49.9 points per game.

The X-factor in Atlanta’s lineup, however, might just be Kyle Korver. Korver has showed signs of a breakout season. The long-distance specialist scored in double digits in a seven of nine games earlier this year as the Hawks climbed to second place in the Southeast Division. But Korver suffered a rib injury last Tuesday in a loss to the Magic and the Hawks have listed him as day-to-day.

With just two teams above .500 in the conference through Thursday’s games, it’s anyone’s game. The new-look Nets and the Carmelo Anthony-led Knicks still have plenty of time to solve their problems. And Paul Pierce, who along with Kevin Garnett was brought to Brooklyn to lead the Nets deep into the playoffs, has confidence things will look up.

“I know it is eventually going to turn around,” Pierce told ESPN.com. “I have been in this situation before. I remember a couple of years ago … I was with a Boston team that was under .500 going into the all-star break. We weren’t playing well, [but] you look up playoff time, we were one quarter away from being in the [NBA] Finals. So, you know, I believe that I will turn this around and our team will turn this around.”