Rose out with tweaked knee; Noah starts suspension

As the Knicks faced mathematical elimination from the playoffs Wednesday against the Heat at the Garden, their two key offseason additions from the Bulls were missing. Mark their absences as symbolic in a season gone astray.

Point guard Derrick Rose and center Joakin Noah were supposed to lift the Knicks back into the playoffs. Instead, Wednesday, Rose was out with a new knee injury and Noah wasn’t even allowed in the building.

Noah began serving the first of his 20-game suspension for violating the anti-drug policy after testing positive for androgen, a performance enhancing drug under the current collective bargaining agreement. Noah was there during early warm-ups but had to leave the premises two hours before tipoff, per NBA guidelines. He’ll sit out the team’s final eight games this season and the first 12 to start next season after an NBA medical expert gave ruled he was “physically able to play.’’

“Obviously it’s not 20 games of the season next year, [but] it’s still a chunk of games,’’ Knicks coach Jeff Hornacek said.

Who knows if Rose, a free agent, will even be with the Knicks next training camp after a season in which his numbers looked good, but his defense and chemistry with Carmelo Anthony and Kristaps Porzingis never came together.

His knees were healthy — until this week. Though he said he does not believe the injury is serious and said he’s “proved [himself ] this year’’ to potential free-agent suitors.

Rose, who’s had surgeries on both knees, felt tightness before the win over Detroit on Monday, but played through it. His knee swelled up the next day and he sat out Wednesday’s first leg of the home-and-home with Miami.

His suitors in free agency need not worry, he said.

“Ligaments or joints, I’d know something,’’ Rose said. “Last injury I had was [a torn] meniscus and I wasn’t able to bend my leg at all. You know the difference. I would know if some- thing serious was going on. I don’t think it’s nothing too serious, but something I have to be aware about.”

Hornacek said he noticed Rose hobbling late in Monday’s game, but the explosive guard still notched 27 points.

“I told him before the game even started I was feeling it,’’ Rose said. “It feels like pressure. Tight. I feel like your leg doesn’t warm up at all. It feels like playing with a stiff leg. I felt it all last game, was able to get through it but still feel discomfort and tightness.’’