The Boston Celtics may have just lost rookie guard Marcus Smart to a serious ankle injury. Smart was injured Friday night in the fourth quarter of the team's game against the Indiana Pacers. He drove to the basket on a fast break and rolled his ankle as we was being fouled.

UPDATE: NESN reports that Smart sustained no serious damage to his ankle. He's been diagnosed with a bone bruise and sprain and is expected to miss 2-3 weeks:

Smart diagnosed with sprain and bone bruise. According to Ainge initial estimate is that he'll miss two to three weeks. — Mark Murphy (@Murf56) November 8, 2014

Preliminary results show a sprain for Smart. Expect him to be out two weeks, maybe longer depending on how cautiously Celts proceed. — Steve Bulpett (@SteveBHoop) November 8, 2014

Much of how soon Smart can get back will be determined by swelling in the ankle over the next day or two. — Steve Bulpett (@SteveBHoop) November 8, 2014

It was so bad that Smart stayed on the floor yelling in pain, and a stretcher had to be brought out for him before he was eventually taken off the court on it. He was injured by Pacers guard A.J. Price going to the rim, and he fell on Lavoy Allen's foot coming down, causing the ankle to roll.

The game was tied at 75 when the play occurred.

The Boston crowd was deathly silent when the play occurred, as it quickly became evident that Smart was seriously injured.

Doctors attending to Marcus Smart (CSN screenshot) pic.twitter.com/XPuoVZxlKl — Chris Forsberg (@ESPNForsberg) November 8, 2014

Marcus Smart being carried out right underneath us. TD Garden very subdued as the game resumes. pic.twitter.com/5H0jfFETxd — Sean Grande (@SeanGrandePBP) November 8, 2014

Marcus Smart signaling thumbs up to the crowd as he's wheeled off the court by Dr. McKeon and company after an apparent leg injury. — Boston Celtics (@celtics) November 8, 2014

Boston did go on a 7-2 run as soon as Smart was forced from the game, but this would still be a devastating loss for Boston if they were to lose their prized offseason acquisition.

Marcus Smart suffered a left ankle injury during the fourth quarter tonight against Indiana. He will have an MRI later this evening. — Boston Celtics (@celtics) November 8, 2014

A 6’4" combo guard, Smart was selected by Boston with the sixth overall pick in the 2014 NBA Draft. He was a two-time All-Big 12 First Team selection. Smart finished his two-year OSU career with 189 steals, the second-most in school history, and averaged 2.94 steals per game in his career, a school record.

During his sophomore season at Oklahoma State he led the Cowboys with 18.0 points, 4.8 assists and 2.9 steals per game. His 2.9 steals per game ranked third in the nation, and he earned AP All-American honors his final year in college.

We'll keep you updated as more information is made available.