The 28-year-old Flores has won 15 of his 17 fights through knockout with his only defeat coming at the hands of former IBF heavyweight champion Charles Martin in a North American Boxing Association title fight in 2014.
Martin's victory set up a successful tilt at the IBF crown vacated by Tyson Fury, and a subsequent unification date with Anthony Joshua.
Parker will fight Flores at Horncastle Arena on December 15th having lost his past two fights.
He lost to world champion Briton Anthony Joshua, who holds three of the four major heavyweight world titles - the IBF, the WBA and WBO titles - in April in Cardiff .
He followed that up with a loss to WBC champion American Dillian Whyte in London in July.
"There is no way this fight goes 10 rounds," the 17-1 Flores says. "I'm going to knock him out."
Flores has also served as a sparring partner for Andy Ruiz Jr ahead of his loss to Parker.
Parker's promoter David Higgins concedes he has some reservations about the fight.
"With Joseph coming off two straight defeats.....a third defeat would be catastrophic for his career," Higgins said.
"Alexander's undoubted punching power makes this an extremely dangerous assignment for Joseph - so it is fair to say I am the most nervous I have ever been before a fight."
Parker, who began his training camp in Las Vegas two weeks ago, said he respected the danger posed by Flores but was confident in his own ability.
"I know what is stake, I need to win and win well. I need to knock him out and I will knock him out. But I can't focus on that. I need to focus on getting better each and every time I get in the ring."
"After a five-year undefeated run that took Joe all the way to the WBO World Title, we now find ourselves in very unusual territory, coming off back-to-back loses," said Parker's trainer Kevin Barry.
"Joe finds himself under huge pressure to not only to win this fight, but to win big and get his career back on track."