Parker's physical shape is especially important because of his desire to throw a lot of punches against Whyte; more than he did during 12 rounds against Anthony Joshua in April.
The New Zealand heavyweight and former WBO world champion will be helped here because he has entered the camp in far better shape than he did the Joshua camp where he arrived weighing about 120kg. Now he is close to the weight he will fight at - about 110kg - which is one less thing to worry about.
"It makes it a lot easier - Kev can focus on skills, techniques and combinations and not focus on losing the weight first," Parker said. "For this fight, we want to throw lots of combinations. We need to be way busier. He throws a lot of punches and we have to throw a lot so we can catch him."
Asked if he needs to use movement and work rate to fight at a pace Whyte can't handle, Parker said: "He fights at quite a high pace. It's important to keep him guessing with movement, but even with the movement, we have to throw a lot of punches. Less movement, more punches, but still be smart with how I box and move and throw. There will be a few changes to what everyone saw in the last fight."
Parker said five or six sparring partners had been lined up for the end of next week. Normally he wouldn't start sparring until week three or four of a camp. "Four of them [sparring partners] are in the top 10 and have fought for world titles. We think each one will bring something that matches Whyte," Parker said.
The Whyte fight, negotiated in a whirlwind 48 hours by Parker's promoter David Higgins and Whyte's promoter Eddie Hearn, is looming as crucial and lucrative for Parker.
A win will send Parker back up the rankings and within touching distance of a mandatory world title shot - and a possible rematch with Joshua.
The Herald on Sunday understands Parker will receive more than $1 million for the bout - a reflection of Higgins' negotiating skills and the buzz around the clash which will be pay-per-view in the United Kingdom.
Englishman Whyte, a 30-year-old who has lost only once as a professional - also to Joshua - is a come-forward all-action fighter. He knocked out Australian Lucas Browne with a spectacular left hook at London's O2 Arena - the venue for Whyte v Parker - last March.
"He's very compact," Parker said. "The left hook is like his default punch. It's probably the main weapon in his arsenal."
Whyte's style is seen as perfect for Parker's but the risk will be ever-present.
A familiar name on a high-quality undercard is Carlos Takam, a fighter who took Parker 12 rounds in 2016. Takam will fight Englishman Dereck Chisora, a man who lost by split decision to Whyte two years ago.
