Tillman is a busy fighter in the sense that he entered the ring 11 times last year, but the same adjective couldn't be used to describe his fighting style. Footage of his 12-round defeat to Australian Lucas Browne last August showed he had feet of stone.
Browne, incidentally, knocked out Liava'a in 69 seconds in December in Perth.
Given that Liava'a's significant chin was untroubled during six rounds with the power-shy Williams - and Tillman survived 12 rounds with Browne - the chance of Williams producing a stunning knockout appears slim.
While the super-fit Williams will certainly have an edge in aerobic fitness and mobility, Tillman is at least a proper fighter.
He has reportedly been sparring with Moyoyo Mensha, who is to fight Chauncy Welliver for a trio of belts including the NZ Boxing Federation heavyweight title on January 28.
According to Boxrec.com, Tillman is scheduled to fight for the vacant WBU International heavyweight title in March.
"Tillman is a quality fighter, so I will have to put in the extra yards over the next three and a half weeks and change my fight plan accordingly," Williams said in a statement. "The fight is going to be a huge challenge."
SONNY BILL WILLIAMS
* 1.91cm, 108kg
* 26yo
* 4 wins (2 by KO)
* 0 losses
* Auckland NZ
CLARENCE TILLMAN III
* 1.96cm,125kg
* 34yo
* 11 wins (6 by KO)
* 8 losses, 2 draws
* New Orleans, US, resides in Auckland.