Heavyweight title on the line as Ruann Visser and Justice Siliga square off

Ruann Visser and Justice Siliga slug it out for the SA heavyweight crown in Pretoria this afternoon, though they might not be the best heavyweights in the country.

They might not even be the best on the bill, with former prospect Flo Simba making another comeback in a six-rounder on the undercard.

But Simba, once touted as a world title contender, is treating his return almost as if he's starting from scratch. "I'm just getting back in. I need to build myself up, not only physically but also mentally.

"Only recently I've realised I need to work on my time in the ring. I need more ring experience."

Simba has been a professional for longer than both Visser and Siliga, and has engaged in more fights than them, but not more rounds.

Visser, with 15 wins and two losses, has 64 rounds, two more than Simba's 62 and eight more than Siliga's 56, from eight wins and six defeats.

More tellingly, Simba hasn't fought for more than a year, and that's not out of his own choice. He counts six cancellations in two years, including a fight against Siliga which he was pulled out of because of his Type 1 diabetes.

"It's all been cleared," said DRC-born Simba, who came to SA as a toddler. "I spoke to the boxing doctor who came to test me in sparring here."

Simba wears a stick-on device on his leg with a flexible plastic needle that tests his sugar. The information is relayed to a monitor handled by his trainer, Jodi Solomon.

He's also allowed to sip on a sports drink to help boost his sugar, though his problem is that his sugar levels normally go up during a fight, presumably raised by adrenaline.

SA-based Zimbabwean Elvis Moyo, a controversial points loser to Simba in 2010 but who has beaten both Visser and Siliga, is predicting a potentially exciting showdown in the main bout.

"Giant King" Visser stands 2.07m tall, but he was unable to use his height advantage against the wily Moyo.

Even so, Moyo reckons Visser is the favourite, largely because he didn't like the way Siliga got dropped by Josh Pretorius in his last outing. "I'm tipping Visser for this one. Siliga, if he gets caught by Visser like he did by Pretorius ... he's in trouble.