Cape Town - Bulls centre Johann Sadie says he is a "stronger, fitter and mentally tougher" player since joining the Bulls from the Stormers.

The Beeld newspaper reports that Sadie and Francois Venter will start in the midfield for the Bulls against the Sharks at Loftus Versfeld on Friday evening.

Both will make their Super Rugby debuts for the Bulls, although Sadie has played seven times for the Stormers. Venter will make his first Super Rugby appearance.

"Everything has changed since I came to the Bulls 13 weeks ago. I'm stronger, fitter, and mentally tougher and I'm burning to put all the last few months' hard work into action.

"Things are done a lot differently here than at the Stormers and each of the regions have their own culture.

"I don't really want to make comparisons but what I can say is that I never realised what my body and mind were capable of before I joined the Bulls. I didn't realise one could be pushed so far (to the limit)," said Sadie.

The 20-year-old Venter believes he's ready for the challenge of taking on the Sharks.

"I also played for the Blue Bulls in last year's Currie Cup and also against the Sharks - so I know what awaits me," said Venter.

Venter will play in the injured Wynand Olivier's place and he's keen to make Olivier fight to get his spot back.

"I have unbelievable respect for Wynand and he helps me a lot but it won’t help just accepting I won't get game time.

"I will push him all the way for a spot in the starting team," said Venter.

The Bulls' clash against the Sharks kicks off at 19:10 on Friday evening.