Jenkins, Ulengo to start against Waratahs
Jenkins pulled out of the first match of the tour against the Force due to an injury, but is fit again and will combine with regular lock partner RG Snyman.
He replaces Marvin Orie, who moves to the bench.
Ulengo, who returned home from Perth before the Force match, has since returned and will start in place of the injured Travis Ismaiel at wing.
Jannes Kirsten is also back at flank in place of Arno Botha, who drops out of the matchday squad.
Marais has swopped his halfback combinations that started against the Brumbies last weekend with Rudy Paige and Tian Schoeman starting, while Piet van Zyl and Francois Brummer move to the bench.
In a similar move, Lizo Gqoboka will start at loosehead and Trevor Nyakane will come off the bench.
Marais also handed a playing opportunity to Jaco Visagie and Pierre Schoeman, replacing Bandise Maku and Werner Kruger on the bench.
Dries Swanepoel also replaces Dan Kriel as back-up backline player.
Bulls: 15 SP Marais, 14 Jamba Ulengo, 13 Jesse Kriel, 12 Jan Serfontein, 11 Bjorn Basson, 10 Tian Schoeman, 9 Rudy Paige, 8 Hanro Liebenberg, 7 Jannes Kirsten, 6 Pieter Labuschagne, 5 RG Snyman, 4 Jason Jenkins, 3 Marcel van der Merwe, 2 Adriaan Strauss (captain), 1 Lizo Gqoboka.
Replacements: 16 Jaco Visagie, 17 Trevor Nyakane, 18 Pierre Schoeman, 19 Marvin Orie, 20 Roelof Smit, 21 Piet van Zyl, 22 Francois Brummer, 23 Dries Swanepoel.
Date: Saturday, May 14
Venue: Allianz Stadium, Sydney
Kick-off: 19.45 (11.45 SA Time; 09.45 GMT)
Referee: Glen Jackson
Assistant referees: Ben O'Keeffe, James Leckie
TMO: George Ayoub
