Rook has a Learning Curve

What's crushing about the left ankle injury sustained by rookie Marcus Smart on Friday night is that he was growing nightly. His NBA lessons were being learned quickly. He was making his mistakes but also making plays, and the education of Marcus Smart was as helpful as the Celtics could have envisioned.

There isn't much to learn from sitting on the end of the bench with a boot engulfing your left leg, which is expected to be Smart's fate for several weeks.

The injury that occurred in the fourth quarter of Boston's 101-98 win over Indiana was rather shocking because it happened on one of Smart's customary fullback-like drives to the basket. He caught a feed from Phil Pressey and sought to split Pacers A.J. Price and Lavoy Allen.

Smart stepped forward with his left foot, looking to spring to the hoop, but his ankle collapsed and he tumbled near the baseline, writhing in pain for several minutes before being taken off the court on a stretcher.

It was serious from the beginning. Smart kept holding his ankle, and reluctantly allowed doctors to touch his leg. X-rays taken at TD Garden were negative, and Smart was taken to the hospital for an MRI.

The Celtics not only lose their prized rookie but they lose one of their best defenders, a backup at two positions, and the ability to see if Smart could develop into their starting point guard next season. It's a damaging blow to the Celtics, who now have just a five-game sampling of Smart's potential.

What we saw was a tenacious defender, an improved shooter, and someone unafraid to respond to adversity. There were several times over the past 10 days when Smart experienced a high and a low in a matter of seconds. Such as Friday, when he blocked Price's layup attempt, grabbed the ball, and took off on a fast break, only to have his layup attempt snuffed out by Damjan Rudez.

Smart's expression after that play was priceless, exhaling because the game is never mastered. What has impressed his teammates is Smart's guile and toughness. Scouts have been raving about his defense. He was not afraid to take significant shots and he also was learning to run the offense.

While the Celtics are trying to win every game and perhaps make the playoffs in the unpredictable Eastern Conference, the primary goal this season is development. The Celtics want Kelly Olynyk and Jared Sullinger to develop into more dependable assets. They want Smart to become a staple in the backcourt. They want Avery Bradley to become a more reliable shooter.

While those goals are still possible, Smart's injury interrupts that evolution.

"Hopefully he can get back sooner rather than later," coach Brad Stevens said. "Because he's really playing great basketball and I'm sure it's really disappointing to be out five games into your rookie year, even if just for a little bit of time."

After the game, the Celtics' locker room was upbeat considering the circumstances. They won an important game. The difference between 1-4 and 2-3 is significant. They proved they could win a close game after losing a pair over the past four days.

And they did it without Smart and Rajon Rondo for most of the fourth quarter. The Celtics announced after the game that Rondo would not accompany the team to Chicago for Saturday night's game, instead having a screw removed from his surgically repaired left hand.

The team will have to rely on its depth and move forward from Smart's injury. The NBA is not a league of long memories. Injured players are mourned briefly and then replaced.

"I know he's a tough kid," swingman Evan Turner said. "So to see him down on the ground was difficult]. I know he's positive. I just told him to stay strong and he's going to come back strong and he said, 'I got you.' "

Now the Celtics move on and Smart will have to wait perhaps months to make the desired impact. Stevens will have to figure out which player will soak up Smart's minutes.

Will rookie James Young get a good look? What about Gerald Wallace, who came off the bench cold when Smart was injured and then hit two free throws and made the game-securing steal?

Those are decisions that will have to be made soon, but one thing is certain — the Celtics will have a different complexion without Smart. He brought a toughness to the team it had lacked since Kevin Garnett departed. While it's premature to call him an elite defender, he was soaring toward that level.

That progress will be on hiatus for a while. Smart will have to deal with an adverse situation, and the Celtics are banking he will return with the same vigor and aggression.