UPDATE:

While it is still not known how long Gobert might be out, we now know the details of his injury, as Shams Charania of The Vertical reports that Gobert suffered a hyperextension and bone bruise of his left knee. He also has no structural damage, which is good news for both Gobert and the Jazz. Hopefully, he will be able to return to the court soon. 

UPDATE:

Gobert is still in the process of undergoing an MRI, but per The Undefeated's Marc Spears, there is no damage to his ACL and MCL:

"Jazz center Rudy Gobert is getting an MRI right now, but a source tells The Undefeated his ACL and MCL are fine."

UPDATE:

Late in the first quarter, the Jazz announced that Gobert has suffered a left knee sprain, and will not return to Game 1. His status beyond Saturday's game is not known. 

Just 17 seconds into Utah's first playoff game since 2012, things got off to an unfortunate start. Rudy Gobert, the team's best big man and a finalist for the Defensive Player of the Year award, knocked knees with Luc Richard Mbah A Moute, and crumpled to the floor. 

Gobert stayed on the ground as play went down the other end of the floor, and struggled to get to his feet once there was a stoppage of play. Eventually, he hobbled off the floor and towards the locker room, but not under his own power. 

We will continue to update this story as details arise ...