Williams and his manager Khoder Nasser are keen to squeeze the fight in before the dual international begins his on-field commitments with the Roosters - and there isn't anything the tricolours can do about it, as it was always a condition of his agreement with club chairman Nick Politis.

A pectoral muscle injury suffered while playing rugby union in Japan has thrown a spanner into the works of Williams' plans to continue football and boxing careers concurrently.

Williams is unlikely to play again for the Panasonic Wild Knights in Japan due to the injury, but he wants to reschedule the lucrative fight against South Africa's Botha at the latest possible date to ensure he will be fit.

The Roosters are pencilled in to host arch-rivals South Sydney in the opening match of the new NRL season on March 7, and the bout looks likely to be held just a fortnight earlier.

It would ensure a disruptive preparation for new Roosters' coach Trent Robinson as Williams returns to rugby league for the first time since 2008.

But Williams' good friend Anthony Mundine said the 27-year-old should be welcomed back to the NRL regardless of his plans.

"My opinion is I'd love to see him play and I love watching him play. Whether it's league or union, I'll watch him," Mundine said.

"Sonny is like me. We bring entertainment - we bring excitement. They love us or hate us. They are going to watch us and respect us.

"He's a phenomenal athlete and footballer and why shouldn't he deserve to be playing at his best in the NRL?

"I'll tell you what, I'll be watching him and I know you will be too, so don't worry about it." AAP