Cooper Flagg, the reigning NBA Rookie of the Year, left the Dallas Mavericks' 121-105 win over the Indiana Pacers on Friday with a left shoulder injury just before halftime after being on the receiving end of a flagrant foul by Aaron Nesmith. 

Mavericks coach Dusty May said that Flagg was in "good spirits" in the locker room, but will be evaluated in the "next couple of days." The Mavericks are set to host the San Antonio Spurs on Saturday before going back on the road to face the Miami Heat on Monday. It's unclear if Flagg will play in either of those games. 

With a minute to play in the first half in Indianapolis, Flagg got a steal and took off the other way on a fast break. It seemed he would have an easy dunk until Nesmith raced in from behind and sent him sprawling with a hard foul. Flagg immediately grabbed for his shoulder, while Mavericks forward Naji Marshall confronted Nesmith under the basket, which led to a big scrum involving players from both teams. 

Here's a look at the play:

After a review, the foul was upgraded to a Flagrant 1 on Nesmith, and Marshall and Nesmith both received technicals. Flagg made both of his free throws before leaving the game for good. 

"Nesmith's a great guy. Heck of a player. I've known him since he was in high school. An unfortunate play. Hopefully Coop's fine, but obviously it's something we wish wouldn't have happened," May said. 

After putting up 24 points in the win, Kyrie Irving explained why the Mavericks were so quick to stand up for Flagg. 

"We've got to set an example for every single one of us, especially Coop, our youngest guy on the team. We gotta protect him, and when we see him go down like that, it doesn't make us feel good," Irving said. "That's NBA basketball, it's a brotherhood you create within that locker room. You can see the difference when teams don't show up for each other and we don't want to be one of those teams, so when anyone goes down, especially Coop or myself or anybody, we gotta have each other's back, and we're a family out here and that's the atmosphere we gotta create."

Flagg averaged 21 points, 6.7 rebounds, 4.5 assists and 1.2 steals last season, and was off to a stellar start in his sophomore campaign. He poured in 32 points on 10 of 17 from the field in the Mavericks' season-opening loss to the Houston Rockets on Wednesday and had 14 points, five rebounds, six assists and three steals on 4 of 6 shooting in 17 minutes on Friday before he was injured. 

After his stellar rookie season, Flagg checked in at No. 25 on CBS Sports' Top 100 NBA players ranking, which was released earlier this month.