Simba, a darling of Golden Gloves promoter Rodney Berman and manager Brian Mitchell, will be among the star attractions on a bill that also features two IBO title fights.
Many pundits have installed Simba as the favourite ahead of his 10-round cruiserweight clash against Bruwer, despite him being knocked out in two of his last three fights at heavyweight.
Bruwer, who suffered the only stoppage defeat of his career in his last outing in November, reckons differently.
"As a heavyweight he (Simba) was pure muscle, and coming down to cruiserweight obviously he has to lose muscle because he hasn't got any fat to lose," says Bruwer, who spent most of his career at light-heavyweight - that's nearly 20kg lighter than Simba was.
"He's going to burn a lot of muscle, I don't think he's going to hit that hard. He's been knocked out twice and coming down a division doesn't do the chin any good.
"I think it's going to give me a good chance to knock him out."
According to one source, Simba himself has admitted feeling stronger at heavyweight. But some believe Bruwer is struggling with his own weight problem.
At Tuesday's pre-fight medical - where fighters have to be within a certain percentage of the agreed limit - Bruwer declined to get on the scale.
He was entitled to do so because only boxers engaged in title bouts are obliged to do so. But that's how rumours start.
Bruwer, who must make the 90kg limit at today's weigh-in, dismisses the suspicion that he has something to hide.
"My weight is cool," he insisted, explaining he had not prepared for a Tuesday weigh-in which, he admitted, "would be a bit of a problem".
Bruwer looks to be carrying extra poundage, whereas Simba is chiselled as always.
But Bruwer, 27, has far more experience with a record of 22 wins (19 KOs), three losses and a draw. In total he has fought 152 rounds.
Simba, 22, has 11 wins and two defeats, but his career rounds tally is just 41. Simba has never been beyond six rounds - familiar territory to "Billy the Kid" Bruwer.
Topping the bill tomorrow is Tommy Gun Oosthuizen, who defends his IBO super-middleweight belt against Serge Yannick, the Cameroon-born Australian.
And Kaizer Mabuza is expected to see off Aussie Steve Wills to lift the vacant IBO junior-welterweight belt.
The tournament will be broadcast on SS2 from 8.30pm.