This NBA season has been full of mental and physical challenges.

The Philadelphia 76ers lost a tough game Saturday night at Memphis, 106-104, then traveled to Oklahoma City, only to find out the game with the Thunder was postponed due to contact tracing for COVID-19.

The Sixers waited a day and flew home.

Philadelphia hosts the Boston Celtics on Wednesday night. Which players will be available for the Sixers is uncertain.

Seth Curry didn't practice Tuesday. His status will be updated on game day. It's unclear how many other players might be out. Injured All-Star Joel Embiid (knee), who missed the game at Memphis, is expected to play. The Sixers are 0-3 without Embiid this season.

Even more maddening for Sixers coach Doc Rivers are ongoing issues with turnovers. Against Memphis, the Sixers got 28 points from Shake Milton but couldn't overcome 22 turnovers.

"It was just a very undisciplined, sloppy basketball game," Rivers said. "Turned the ball over down the stretch the last two times. Disappointing loss to me. Very winnable game and just didn't get it done."

Despite the uncertainty with the roster, getting Embiid back would be a huge boost.

"There is no concern, and I can't say this is something you will see, either," Rivers said. "But when something does pop up, we are going to jump on it and we are going to be very smart this early in the season."

The Celtics try to rebound from a 105-75 loss to New York on Sunday.

Boston's Jayson Tatum could miss his third straight game due to COVID issues. Tatum hasn't played since Jan. 8, and Wednesday is the earliest he can return.

"Everybody's got their own different testing protocols they have to go through and the timeline that they have to be on," Boston coach Brad Stevens said. "So I don't know what to expect for Wednesday night. We'll just play it by ear and go with the information we get every morning."

The Celtics had to be encouraged by the return of All-Star Kemba Walker from a left-knee injury, which cost him the first 11 games this season. Walker left Sunday's game in the third quarter with a rib injury, but said he was fine after the game.

"It felt really good to be out there," Walker said. "Really good. I almost forgot how it felt. Free, which I haven't been for a very, very, very long time. It feels weird not having (knee) pain, if that makes sense."

Walker shot 3-of-13 from the field in a 20-minute restriction limit and missed 7 of his 8 attempts from 3-point range. He practiced Tuesday.

From Jan. 3-15, the Celtics won five straight. Despite Jaylen Brown's 25 points, they were drubbed by the Knicks and managed a season-low scoring output.

Philadelphia won't be an easy place for Boston to play. The 76ers are 7-1 at home this season.

"I don't believe that's who this team is," Stevens said. "We had a clunker. You try to have as few of those as you can. We just looked like we were in mud today."

--Field Level Media