We have some bad news on the Boston Celtics front.

According to Adrian Wojnarowski of ESPN, Celtics guard Marcus Smart could be sidelined for the first two rounds of the NBA playoffs due to a torn oblique on his left side.

Smart initially suffered his injury in the Celtics' loss to the Orlando Magic on Sunday evening. The 25-year-old guard had to be helped off the floor after suffering an injury to his side. Trying to crash down into the paint on defense, Smart collided with Magic big man Nikola Vucevic and immediately crumpled to the ground in pain. He tried to play through the injury, but went down again on the next possession, and had to be helped to the locker room.

Smart has been the team's starting shooting guard for much of the season, serving as the defensive stopper and enforcer. In 80 appearances and 60 starts this season, Smart averaged 8.9 points and 4.0 rebounds per game on 42.2 percent from the field and 36.4 percent from beyond the arc.

He recently won the Red Auerbach award for the first time, the team's honor for which player best exemplifies being a Celtic.

There's no doubt that the loss of Smart will be a major blow to the Celtics entering the postseason. Although they enter with home-court advantage in the first round of the playoffs, head coach Brad Stevens will have to shuffle his lineup once again after finally finding continuity with the five-man lineup of Smart, Aron Baynes, Al Horford, Jayson Tatum and Kyrie Irving.

Expect Stevens to go with either Jaylen Brown or Gordon Hayward -- former members of the Celtics' starting lineup -- to replace Smart.