Philadelphia’s Joel Embiid and Milwaukee’s Khris Middleton are among the injured stars expected to be on the sidelines as the second round of the NBA playoffs begin on Sunday. The top four seeds in both the Eastern and Western Conference advanced from the opening round, but few managed to get through unscathed. Embiid, the NBA scoring leader from Cameroon, suffered a right orbital bone fracture and concussion in the 76ers’ series-clinching win at Toronto and is out indefinitely. The 7-foot star was already nursing a thumb injury when he was struck in the face by the left elbow of countryman Pascal Siakam of the Raptors. “I think he broke my face,” Embiid said. “But it’s all good in the playoffs.” Embiid 26.2 points and 11.3 rebounds against Toronto. He had 30.6 points and 11.7 rebounds in a regular season and is a finalist for the NBA Most Valuable Player award. Middleton, a 30-year-old forward, is expected to miss most if not all of the second round with a sprained left knee ligament. Defending champion Milwaukee, sparked by Greek star Giannis Antetokounmpo, will open a best-of-seven series against Boston on Sunday in the East while Golden State visit Memphis for their West opener on Sunday. The other two conference semifinals begin Monday with Philadelphia at Miami and Dallas at Phoenix. East top seed Miami had four standouts who didn’t practice on Friday, including forward Jimmy Butler with a knee injury and Kyle Lowry with a hamstring concern. Butler averaged 21.4 points, 5.9 rebounds and 5.4 assists a game for the Heat this season while guard Lowry, who won an NBA title with Toronto in 2019, had 13.4 points, 7.5 assists and 4.5 rebounds a game. Memphis was without New Zealand big man Steven Adams, in COVIS-19 protocols, for a series-clinching win over Minnesota. Golden State’s Andre Iguodala was expected to be re-evaluated next week for neck pain aggravated during the Warriors’ first-round series against Denver. Boston’s Jaylen Brown has had hamstring tightness but was expected to play in Sunday’s opener against the visiting Bucks. The Celtics are in the second round for the fifth time in six years and are rested after pulling off the only first-round sweep in eliminating Brooklyn. They closed the regular season 26-6 and NBA Defensive Player of the Year Marcus Smart anchors the NBA’s best defensive unit, a group that will try to make life difficult for Antetokounmpo. That includes Jayson Tatum, who averaged nearly 30 points a game in round one. The 76ers, who lost to Atlanta in last year’s second round, would need star guard James Harden, forward Tobias Harris and playmaker Tyrese Maxey to step up if Embiid misses major time against the Heat. Miami big man Bam Adebayo could play a pivotal role in the series if he can dominate in Embiid’s absence. Memphis boast NBA Most Improved Player Ja Morant and impressive Desmond Bane leading a young and talented Grizzlies unit. But they face a Golden State squad that has quickly revamped and boasts star guards Stephen Curry and Klay Thompson, inside defensive force Draymond Green and third-year guard Jordan Poole. Curry has recovered from a left foot injury that left him coming off the bench much of the first round and his backcourt battles against Morant could be series highlights. Poole made the most of his starting role in Curry’s recovery to deliver a scoring punch as a reserve. “I didn’t really come in with any expectations,” Poole said. “I didn’t know what to expect because this was my first time being here. But I definitely learned a lot.” Green is the chief frontcourt fixture back from the Warriors’ NBA title runs and coach Steve Kerr trusts him to handle any position on the floor. “Draymond has the green light to basically do whatever he wants,” Kerr said. Phoenix and Dallas are healthy now that the Suns’ Devin Booker and the Mavericks’ Luka Doncic are back. Doncic was nagged by a left calf strain but recovered to help spark Dallas over Utah while Booker missed three games with a right hamstring strain as Phoenix ousted New Orleans. Suns guard Chris Paul hit all 14 of his shots in a 33-point effort in Phoenix’s closeout triumph.