Knicks center Isaiah Hartenstein returns from injury; Thibodeau ‘encouraged’ by Mitchell Robinson’s progress

The Knicks got back one key big man on a day another went down.

Isaiah Hartenstein returned to the Knicks’ starting lineup for Saturday’s 125-109 win against the Miami Heat, during which Julius Randle left with a concerning right shoulder injury.

Hartenstein had missed the previous two games with an injured left Achilles. The 7-footer scored four points and six rebounds in 16 minutes, saying afterward he was on a minutes restriction.

“It feels good, so that’s a great little test,” Hartenstein said.

Hartenstein entered Saturday as a game-time decision and made it through warmups feeling well enough to play.

The 25-year-old has filled in admirably for primary center Mitchell Robinson, who hasn’t played since Dec. 8 due to an ankle injury that required surgery. Hartenstein entered Saturday averaging a career-best 8.5 rebounds per game in 43 appearances, including 17 starts, and has recorded five games with at least 15 boards this month.

“Where you are in the season, virtually every player is dealing with something right now,” Knicks coach Tom Thibodeau said. “But we’re not going to put him in harm’s way. So as long he’s good, he’ll play.”

Hartenstein left in the third quarter of the Knicks’ Jan. 20 win over the Raptors with what the team initially called an ankle injury. The Knicks later listed Hartenstein’s injury as left Achilles tendinopathy.

New York went 2-0 without Hartenstein, with Jericho Sims starting both games.

Randle, meanwhile, was in clear pain after crashing to the Madison Square Garden court on a fourth-quarter drive that ended with a collision with Jaime Jaquez Jr. Randle ran into the locker room with a trainer shortly afterward.

Thibodeau said Randle was still being evaluated after the game, while ESPN reported the two-time All-Star suffered a dislocated shoulder. He was set to undergo an MRI after an X-ray revealed minimal damage, according to the report.

Before the game, Thibodeau said Robinson is “doing a little bit more” in his rehab every day but had not been re-evaluated.

“He’s lifting,” Thibodeau said. “He looks like, I don’t know, bodybuilding. Whatever it is that he can do, and it’s a step-by-step progression. So he’ll be in the pool, he’ll be on the bike and then eventually get to be where he can shoot.”

Thibodeau continued, “He’s shooting a little bit, shooting out of the chair at this point. Just following protocols and getting treatments. He’s been great. He’s in great spirits. So we’re encouraged. Everything’s positive so far. Just let him go through it, and then when he’s ready, he’s ready.”

The Knicks were denied a Disabled Player Exception for Robinson, indicating a belief by the NBA and doctors that the 7-footer will be able to return this season.

New York also added depth in acquiring forward/center Precious Achiuwa, who arrived in the late-December deal with the Raptors that brought over OG Anunoby.

Originally a first-round pick by the Heat, the 6-8 Achiuwa played at least 21 minutes and recorded at least nine rebounds in each of the last three games.

“I think each experience teaches you something,” Thibodeau said of the 24-year-old Achiuwa. “He probably benefited from coming in with Miami and then going to Toronto. Those are two really good experiences for him.

“The more you go through things, the more you learn,” the coach continued. “And I think he’s adapted quickly and we’re still getting to know him. I thought the last couple games, he played really hard and really well. Just fit in and bring energy to the game.”