NEW YORK — Greg Monroe was working out, quite frankly preparing for next year when the 76ers called. A player who three times in his career averaged more than 15 points per game, Monroe has slipped into journeyman status. The 28-year-old signed a 10-day contract with Boston on March 24, but wasn’t re-signed.

So Monroe, the Sixers 6-foot-11, 265-pound reserve center, went back to the gym to stay in shape.

“I was working out basically for the offseason,” Monroe said before the Sixers practiced in New York on Friday in preparation for Saturday’s Game 4 of their Eastern Conference opening series with the Brooklyn Nets at the Barclays Center. The Sixers lead the series two games to one.

Next year had to wait for Monroe when the Sixers signed him as a free agent on April 4. He then played in three regular-season games and was only supposed to be an insurance policy.

The policy kicked in when Joe Embiid couldn’t play in Thursday’s 131-115 win over the Nets due to left knee soreness. Monroe got the start and besides missing several close-in shots, accredited himself well.

He scored nine points on 4-of-13 shooting, but also grabbed 13 rebounds in 24 minutes and 33 seconds.

Sixers center Greg Monroe works-out with the basketball during practice at Basketball City in New York, NY on Friday, April 19, 2019.
YONG KIM / Staff Photographer
Sixers center Greg Monroe works-out with the basketball during practice at Basketball City in New York, NY on Friday, April 19, 2019.

“It felt good and it has been a while since I played that many minutes,” he said. “I was a little rusty but it was definitely good to be out there in a playoff atmosphere on the road. It was cool.”

When he blamed rust for his shooting, he said he also could have had more rebounds.

“I feel I missed a few of them as well,” he said.

Still, he had six offensive rebounds, just one fewer than Embiid in the first two games and three more than Marjanovic has in that time.

The Nets could be playing more small ball, especially with backup center Ed Davis out with a right ankle sprain.

Despite that, Nets forward Jared Dudley, who could find some minutes at center, thinks the Sixers won’t be playing much small ball whether Embiid plays or not.

“I think they’ve had success of rebounding," Dudley said on Friday. "Boban has played well, Greg Monroe for that start played well, and obviously when Joel plays. I don’t see that.”

While it wasn’t announced until about 15 minutes before game time that Embiid wouldn’t play, Monroe was given an indication Thursday morning that he could be playing.

“Joel told me in the morning that he didn’t know for sure, but said to be prepared to play,” Monroe said. “I knew all day I was most likely going to start.”

He made the most of his chance.

“I still think it is a helluva story and certainly [Thursday] he helped us win a playoff game without Joel Embiid,” Sixers coach Brett Brown said. “I thought that he was excellent [Thursday] in so many areas and would have been off the charts if he had finished [his shots].”

While Monroe fared well, especially considering his lack of recent activity, Thursday was the third straight strong playoff game for another backup center, 7-foot-3 Boban Marjanovic. On Thursday, he had 14 points, eight rebounds and hit all eight of his free throws.

Sixers center Boban Marjanovic lays-up the basketball against the Brooklyn Nets in game three of the Eastern Conference playoffs on Thursday, April 18, 2019 in Brooklyn.
YONG KIM / Staff Photographer
Sixers center Boban Marjanovic lays-up the basketball against the Brooklyn Nets in game three of the Eastern Conference playoffs on Thursday, April 18, 2019 in Brooklyn.

For the series, he is averaging 14.3 points and 6.3 rebounds while shooting 61.5 percent from the field and is 11-for-12 (.917) from the foul line.

Marjanovic says he didn’t try to do anything extra with Embiid out.

“I did my role,” he said. “I come in the game to help my teammates and protect the basket.”

Embiid was doing some shooting prior to Friday’s practice, but the Sixers media availability was before practice. Brown said he honestly doesn’t know if Embiid will play on Saturday.

In Friday’s NBA injury report, he is listed as doubtful for Saturday’s game.

Ben Simmons, coming off a 31-point, nine-assist effort, praised both backup centers, who combined for 23 points and 21 rebounds in just under 43 minutes on Thursday.

“They are huge, guys who come in and do their job," Simmons said. "Even if Joel is not playing, they can score the ball rebound, they block shots. I think it is the way they are playing, knowing their roles, is huge for us.”

Inquirer staff writer Sarah Todd contributed to this report.