A win in this state, would bring Trump closer to become the GOP presidential nominee and make it difficult, if not impossible for his two remaining rivals Senator Ted Cruz from Texas and Governor John Kasich from Ohio to prevent the billionaire real estate mogul from such an eventuality.
The NBC-Wall Street Journal poll released today said that Trump is leading against Cruz by 15 points. Trump has support of 49 per cent likely voters and Cruz 34 per cent, followed by Kasich at 13 per cent.
Sanders said on Sunday his path to nomination is difficult, but not impossible.
Trump reiterated that he is the presumptive nominee.
"Yes, it's over. I think it's over now, but it's over," he told Fox News.
"Cruz cannot win, he's got no highway, he's got nothing, he's way behind. I'm leading him by millions and millions of votes and I'm leading him by 400 or 500 delegates. He can't win," Trump said.