76ers star Joel Embiid out for Game 1 vs. Celtics - ESPN

The Philadelphia 76ers ruled out NBA MVP finalist Joel Embiid for Game 1 of their Eastern Conference semifinal series due to an LCL sprain in his right knee.

There is optimism surrounding Embiid's potential availability for Game 2, sources told ESPN's Adrian Wojnarowski.

«He's out today,» 76ers coach Doc Rivers said about 90 minutes before tipoff, «and we'll see moving forward.»

Rivers said Embiid shot some after his shootaround, but he hasn't done any running yet. He was also seen getting up shots after the team's practice Sunday.

When asked what it will take for Embiid to get back on the court, Rivers said it'll just be a matter of the doctors telling him that he'll be available to play. Paul Reed started in Embiid's place at center.

Embiid suffered the injury when he landed awkwardly after contesting a drive by Brooklyn Nets forward Cam Johnson in Game 3 of Philadelphia's first-round sweep on April 20.

Philadelphia went on to win Game 4 to close the Nets out two days later, with Rivers saying after that game it was «probably less than 50 percent» Embiid would be ready to go for the start of the Eastern Conference semifinals.

The 76ers were given an additional couple of days of rest when the Atlanta Hawks pushed their first-round series with the Celtics to six games, moving the beginning of the series to Monday rather than Saturday.

Ultimately, though, it wasn't enough time for Embiid to get on the court. Philadelphia will now have to try to replicate its success throughout the season without Embiid, as the 76ers are now 12-5 without their superstar center after the Game 4 win over the Nets.

Both Rivers and Celtics coach Joe Mazzulla said Philadelphia will play faster and spread the floor more with Embiid sidelined.