Newcastle boss John Carver accused Mike Williamson of getting sent off "on purpose" after his side's 3-0 defeat at Leicester.
Newcastle, who have now suffered eight straight losses, endured a dismal trip to the King Power Stadium.
Leicester were ahead inside the opening minute as Leonardo Ulloa rose to head home a corner, and Wes Morgan made it 2-0 16 minutes later.
Ulloa then converted a contentious penalty after Emmanuel Riviere was deemed to have pushed Marcin Wasilewski early in the second half, and Newcastle's fate worsened after both Williamson and Daryl Janmaat were sent off after collecting second yellow cards.
Williamson was sent off in the 62nd minute after he sent Vardy crashing into a TV camera with a late knee-high challenge, having been booked just seven minutes earlier, and Carver said: "I thought he'd done that on purpose -- it looks like he did.
"The ball was off the pitch -- he had no need to make the challenge. He will miss two games. Is it an easy way out?"
Janmaat was sent off after receiving his second yellow card for a tackle on Vardy just before the end of the match.
Carver said: "I got keeper Tim Krul to speak to Daryl Janmaat -- I told him to stay calm and he didn't. The game had gone away from us. We can't keep shooting ourselves in the foot."
The Newcastle boss was also damning in his assessment of the overall performance.
"On a scale of one to 10, it is a minus 10," he said. "I can't accept it. I wish the players had as much determination and fight as I had. We can talk about systems and players but if we're not willing to compete, get your head onto the ball and risk getting an injury, you won't get anywhere."
Leicester boss Nigel Pearson, who faced criticism for his comments to the media after the defeat to Chelsea in midweek, defended Carver after the game.
"It's not for me to make judgement on what's going on, but clearly it remains hard for somebody of his core values to continue to be pushed in front of cameras and try to justify results," he told BT Sport.
"It's clear they're good players. What they need to do is to prove that to themselves as much as anybody else. I hope they find the answers.
"Whatever happens, John Carver will come out of this season, maybe not with the prestige that he would like, but I know he's absolutely committed to his job and I wish him well.''