The Knicks’ shooting-guard glut will be lighter.

The Knicks officially said Monday that free-agent signee Reggie Bullock won’t be ready for the regular season and will be re-evaluated in November after undergoing spinal fusion surgery in July, and Damyean Dotson won’t play any preseason games after undergoing shoulder surgery last spring.

The Bullock bulletin was no surprise, as The Post had reported Bullock would need up to six months of recovery, pushing his potential return all the way to January.

However, the Dotson announcement was a mild surprise. When his surgery was announced last May, the Knicks said he would be ready for training camp, but the expectation now is he won’t return before the start of the regular season. Dotson will do non-contact drills during training camp.

Dotson told The Post in June he played with a shoulder tear last season that wasn’t discovered until a postseason MRI exam.

GM Scott Perry gave no assurances the Knicks would pick up the fourth-year option on point guard Frank Ntilikina’s rookie contract, worth $6.2 million, by this month’s deadline. “We have until October 31 to do that and we won’t discuss any contract things in detail so that’s all I’m going to tell you right now,” Perry said.

Julius Randle said he’s hoping to be a mentor for center Mitchell Robinson. “As a leader, I’m going to try to maximize his potential,’’ Randle said. “I know I can score. One of my goals is to make everyone better.’’ … New signee Bobby Portis — on recommendation from his former team, the Wizards — dropped from his end-of-season weight of 263 pounds to a current 249. “It will be a joy to watch us this season,’’ Portis said. … Newcomer Elfrid Payton, who played for New Orleans last season and is a Big Easy native, says he knew of Chalmette High’s Robinson a few years back and “tried to get him on my AAU team. It didn’t work out.’’ … Kevin Knox said he’s bulked up considerably but gained only three pounds, attributing it to more muscle weight. … Duke coach Mike Krzyzewski has been invited to training camp to watch RJ Barrett, one of his former stars.