There’s one person even angrier than Knicks owner James Dolan about the 2-4 start and Sunday’s San Antonio slaughter.

That’s part-time power forward Kenyon Martin, who had to watch the entire 120-89 Spurs’ nightmare from the bench. He was shackled by the Knicks medical staff’s new platoon system with Amar’e Stoudemire. On Tuesday, Martin was snappish about the whole subject — another sign of the team unrest.

With coach Mike Woodson ready to change his starting lineup Wednesday in Atlanta in The Guarantee Game, possibly inserting J.R. Smith, the Knicks are a mess.

Martin, the backup battling chronic ankle issues, trashed the Knicks’ performance and said he wishes he could have been let loose on Tim Duncan and Tiago Splitter in the disgrace at the Garden. That night, Dolan guaranteed victory in Atlanta on stage at a Manhattan club while playing with his blues band.

“Sunday wasn’t easy by any stretch of the imagination not just for me but for the whole organization — to go out there and lay an egg like that on your home floor,’’ Martin said after Tuesday’s practice. “People pay hard-earned money to come see us play. We shouldn’t put a performance like that out there.’’

Woodson explained he didn’t play Martin in Sunday’s game because the score was too lopsided and wanted to stick to the platoon with Stoudemire in which they rotate games.

“It wasn’t worth doing it,’’ Woodson said.

However, Woodson has said the platoon isn’t set in stone and he could play both players if it’s not a back-to-back scenario.

The whole arrangement appears to be bugging Martin and it has been brewing since preseason when he wasn’t thrilled about playing in only the finale to rest his ankles.

Woodson said Martin will play in Atlanta and Stoudemire will sit. But Martin will be back on the pine Thursday when Dwight Howard, Jeremy Lin and the Rockets invade the Garden.

Martin is also on a 15-to-20 minutes restriction as set by the Knicks medical staff. Martin said it was “difficult’’ to sit during the San Antonio debacle.

“That’s been y’all and Woody,’’ Martin said edgily of the platoon and minute-restriction guidelines. “I’ve told you all I’m fine. Every time you ask me, I’ll give you the same answer, I’m fine — whatever the minutes is.’’

Referring to Tyson Chandler’s broken leg, Martin snapped: “Tyson wasn’t there but I was available. Tyson couldn’t play.

“It was difficult for me to watch any game from the bench, not just a loss. I want to play. I’m a competitor, man. It’s all about winning. It’s all about the team. [But] I want to play.’’

When asked if he’s certain of the platoon guidelines, Martin railed: “You keep talking to Mike about the guidelines. I’m going to worry about us getting better as a team.

“I told you all before. I’m not going to go back and forth with the medical and those numbers. You keep throwing out these minutes. I don’t care about all that. … Guidelines are something for the papers.’’

Last month, Martin said he wouldn’t “press the issue’’ in preseason, but would during the regular season. With the Knicks defenseless against San Antonio, Martin’s energy and toughness could have been used.

“We got to play defense at the beginning of the game like we’re down. We can’t wait to be down and then turn the switch on,’’ Martin said. “By that time we’ve given teams confidence. We just have to have a sense of urgency from the beginning of the game. We can’t think because we’re the Knicks, we can beat every team. A lot of last year isn’t holding up. Teams have gotten better. Teams got pride.’’

Something lacking so far with the Knicks.

“When you’re 2-4, nobody is playing particularly well,’’ Woodson said. “If they were, we wouldn’t be 2-4.’’