GREENBURGH, N.Y. — Derrick Rose is going to have to learn the Knicks’ offense on the fly.

Coach Jeff Hornacek acknowledged after Monday’s practice that it doesn’t seem likely that the team’s new point guard will be back in New York in time to play in either of the final two preseason games.

Rose, who is the subject of a sexual assault civil trial, has been in Los Angeles since Oct. 5, and the earliest he is expected to rejoin the team is Wednesday. The Knicks will play the Celtics on Wednesday night in Boston and conclude the preseason against the Nets on Thursday night.

“Hmmm, I don’t know,” Hornacek said when asked if he will play Rose before the start of the regular season. “If we go through some things in the morning with him the day of [the Nets] game — it’s a back-to-back situation, so I don’t think we’d get a chance to — but if somehow we could get a couple of guys to work with him, maybe . . . But we won’t push that.”

Rose, who was brought in to run the offense, has missed all but the first preseason game against the Rockets in Houston. In his absence, undrafted rookie Chasson Randle has taken advantage of extra playing time, averaging 7.7 points in three preseason games and making 56 percent of his three-point attempts. The Knicks announced Monday, however, that Randle will miss three to four weeks with a broken orbital bone around his left eye. Randle broke the bone in practice Wednesday.

With Randle and Rose out, the Knicks have only Brandon Jennings at point guard. Hornacek, however, doesn’t seem worried.

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“Sasha [Vujacic] has obviously run this stuff before, so we can get him back there, too,” he said. “If Ron Baker makes the team, maybe Ron could play a few minutes there. Obviously, we want to have our full guys in there, but we’ll just make do. Other guys will have to step up if certain guys can’t play.”

There was some good news on the injury front Monday, as Kristaps Porzingis said he believes he will be ready to play Wednesday night in Boston. He sat out a second straight day of scrimmages to rest the groin strain he suffered Saturday night against Boston.

Carmelo Anthony said fans are going to have to temper their sky-high expectations for Porzingis.

“There’s still a learning curve for him,’’ Anthony said. “Last year, nobody knew what to expect — all new to everybody. This year, he’s going to be a focal point of the scouting report, trying to figure out how to stop him. It’s a matter of being smarter and learning the game more. He still doesn’t know the game that much. He’s still a young second-year player.

“We put too much pressure on him to kind of be great so fast. I just want him to get the opportunity to grow as a player. He doesn’t know everything right now. He’s just 21, second year in the league.”