Tobias Harris took a scary fall on the basketball court that could've seriously injured the guy, or possibly even killed him -- but fortunately, it looks like he's going to be okay.

The 76ers star was playing in Sunday's game against the Boston Celtics, when at one point late in the third quarter, he went up for a defensive rebound ... but got his legs clipped by Jayson Tatum midair, which tilted his body and made him land hard on the paint headfirst.

You could see he was in excruciating pain as he writhed on the floor and couldn't get up at first. The refs stopped the game and the Philly's medical staff rushed out to the court to evaluate him. It appeared they signaled for trauma too, which meant it was serious.

It also looks like there might've been some blood spattered on the floor, which the med team was quick to wipe up as well.

The good news is that Tobias was able to get up and walk off the court on his own accord. He's said to have suffered a left eye laceration and was being evaluated for a concussion in the locker room.

It could've been much worse ... thank goodness it wasn't.