New Orleans Pelicans guard Rajon Rondo (9) looks on during the New Orleans Pelicans open practice at Smoothie King Center, New Orleans LA on September 30, 2017.

CHICAGO — To hear Alvin Gentry tell it, Rajon Rondo has already made a major impact on his young Pelicans prior to playing his first regular-season game with the club.

When that might take place, exactly, is up in the air.

A sports hernia kept the four-time All-Star point guard from playing in Sunday night’s 108-95 preseason victory over his last employer, the Chicago Bulls, and Pelicans coach Alvin Gentry would not speculate on the extent of the injury.

Gentry said a timetable for Rondo’s return should become more clear when he sees a specialist in Philadelphia on Monday, though sources familiar with the situation said the initial expectation is Rondo will be out for approximately four weeks.

“I’m not a medical doctor,” Gentry said. “We’ll see what happens after he sees a specialist.”

E’Twaun Moore took Rondo’s place in the lineup as Gentry gave his starters regular-season minutes because he doesn’t plan to show the Memphis Grizzlies much in the preseason finale on Friday with the teams also set to meet in the opener on Oct. 18.

All-Star big men Anthony Davis and DeMarcus Cousins both played over 34 minutes, with Davis treating his hometown fans to 37 points and 15 rebounds and Cousins going for 22 points, nine rebounds and nine assists.

Jrue Holiday, who moved over from the point to the two-spot with Rondo’s arrival, had 19 points on 8-of-12 shooting from the field and added five rebounds and three assists.

Moore (nine points, nine rebounds) and Ian Clark (seven points, seven assists) also figure to see additional ballhandling responsibility in Rondo’s absence.

The 31-year-old Rondo’s leadership can’t be replaced, though, at least not by anyone Gentry has ever coached.

“Best I’ve been around in 30 years in the league as far as a guy who really takes young players under his wing and tries to teach them,” Gentry said. “He’s just a great leader to have on your team. If you want to have a mentor in this league, I would suggest him.”

If the end of last season is any indication, Rondo, who signed a one-year, $4.5-million free-agent deal with the Pelicans, still has something left to offer between the lines as well.

The Bulls thrived last season after Jimmy Butler and Dwayne Wade gave Rondo the keys to the offense, and he drove them to a 2-0 lead over the top-seeded Boston Celtics in the first round of the Eastern Conference playoffs before going down with a thumb injury.

The Celtics won the next four games.

Gentry believes Rondo can have a similar impact on the Pels, particularly as they explore ways to make the Davis-Cousins experiment a success.

“He is going to be a big help in that situation,” Gentry said. “He has played with DeMarcus already (in Sacramento). He is trying to find out about Anthony’s game. He spends a lot of time studying guys.

“Every single practice we have, he puts it on his iPad and watches it again. Every single game he does the same thing. Obviously he has a huge impact on the game. You can see what happened in the two games in Boston last year. He controlled the whole thing, and it was a struggle without him. He has the ability to have that kind of impact on our team, too.”