The Celtics are still unsure whether Marcus Smart will be able to play again this season. They are still waiting for a second opinion after he suffered a torn tendon in his right thumb, but his chances of a return don't look great. According to a report from Mark Murphy of the Boston Herald, the Celtics don't know if it's a "50 percent chance or a 30 percent chance."

Some simple math will tell you that neither of those percentages are very high, and it seems quite likely that Smart doesn't return this season.

Smart is one of the Celtics' most valuable defenders. His ability as a guard to switch on to bigger players makes him one of the NBA's best on that end. There's a possibility that Smart can try to play through the injury, but that depends on the severity of the tear. Players have played through thumb and finger injuries before, and Smart's a tough dude. He shouldn't risk further long term injury for the sake of this one season. Even with how injured the Celtics as a whole are. 

The Celtics can't afford to lose Smart for the season, let alone a significant amount of time as there isn't any real way to replace him. Boston is already facing injuries to multiple key rotation pieces. Any more and the entire roster might just fall apart.