CHICAGO -- A slim specter of hope turned sharply to the worst thought imaginable for Bulls fans late Saturday afternoon -- how do they survive without Derrick Rose?

An MRI revealed a torn ACL in the left knee of the reigning MVP, sustained with 1:22 left in the Bulls' 103-91 victory over the Philadelphia 76ers in Game 1 of their first-round playoff series.

Derrick Rose's teammates were incredulous that people were asking whether he should have been in the game late in the fourth quarter Saturday. Dennis Wierzbicki/US Presswire

The injury occurred on an awkward twist during a routine drive that hasn't been routine in a while, and in the worst-case scenario, may never be routine again.

Up until then, it was ho-hum as playoff games go. The Bulls were on their way to a relatively easy victory. The storyline was Rip Hamilton's performance in support of a much-improved but still-not-quite 100 percent Rose, a great sign for a team looking for that one more piece.

Up until then, even the Sixers making a mini-run to cut a 20-point Bulls lead to 12 in the previous two minutes, hardly felt like a time for panic. And while there may have been a few questions afterward, Rose's presence on the court with a minute and a half remaining did not necessarily signal a call for debate, much less coach Tom Thibodeau's head.

Up until then, there was every reason to believe Rose was well on his way back; the Bulls' starting lineup was finding its rhythm; a long run in the NBA playoffs was a reasonable thought.

Up until Rose went up with a grimace and came down clutching his left knee, the United Center was a hopeful, happy place.

Afterward, not even the Bulls' victory could cut through the quiet of a stunned Chicago locker room as players shook their heads and whispered to each other, unable to mask their fear over what would turn out to be Rose's sixth and most damaging injury -- both to him and to his team -- this season.

"My heart," said Hamilton, "kind of dropped ... It was scary, not for just us. but the whole city of Chicago."

Taking this in the context in which it belongs, the sight of Rose lying prone on the court was indeed frightening. And immediately, it brought into razor-sharp focus the X factor of the Bulls' chances this postseason: Rose's delicate health.

The Bulls can beat the Miami Heat in the Eastern Conference finals if Rose stays healthy, the pundits prognosticated. The tremendous contribution this season of the Bulls' bench, the improvement of Carlos Boozer and addition of a healthy Hamilton can carry this team all the way only if Rose is OK.

As expected, Thibodeau was stoic in the face of this latest adversity, even before a diagnosis was made.

"It's a part of the game," he said. "There's going to be injuries. A guy can get hurt in practice, he can get hurt in the first five minutes of a game, he can get hurt at the end of a game. He can get hurt at any time and you've got to deal with it. That's part of this game. He's had a lot of injuries this year. It's been unfortunate. But we do have more than enough to win with it. So whatever the circumstances are, we'll deal with it."

Immediately, the questions began over whether Rose, who played a little more than 37 minutes, should have been on the court at that late stage given his relatively fragile condition. But Thibodeau was resolute.