The NBA is likely to begin an investigation later this week into the Philadelphia 76ers surrounding the player participation of All-NBA center Joel Embiid, sources told ESPN on Wednesday.

Embiid didn't play in the preseason for what the team called left knee injury management and will miss three games this week -- Wednesday's season opener against the Milwaukee Bucks, Friday against the Toronto Raptors and Sunday against the Indiana Pacers.

It's typical for the NBA to review a team anytime a superstar player misses a national television game, as per the player participation policy.

The 76ers said Embiid is "responding well to his individualized plan" and will ramp up his return-to-play activities this week, including going through scrimmages.

This is part of the new normal for Embiid this season, according to sources, a strategy to keep the former NBA MVP healthy for the postseason. The plan has been expected to include periodic time off during the regular season and routine evaluations from doctors and the 76ers medical staff, those sources said.

Sixers president of basketball operations Daryl Morey told ESPN's Tim Bontemps earlier this month that Philadelphia would try to keep both Embiid and Paul George out of back-to-backs this season.

"We're going to be smart about it. Part of being smart about it is having both Paul [George] and Joel probably not play many back-to-backs, if any," Morey said.

Embiid also told Bontemps that, "If I had to guess, I would probably never play back-to-backs the rest of my career."

Embiid has lost 25 to 30 pounds, with the hope to lose more, and will continue to wear a brace on his left knee despite it being something that he would prefer not to do, instead opting to keep it as structurally stable and protected as possible.

Embiid played in only 39 games last season because of knee injuries. He returned in time to play against the New York Knicks in the playoffs, but did so at less than 100% -- and that was before he was dealing with a sudden onset case of Bell's palsy during the series. He went on to play for Team USA this summer, helping the Americans win a fifth straight gold medal at the Paris Olympics.