The Bulls have named their 26 strong squad to tour Australia and New Zealand with matches against the Rebels, Waratahs, Highlanders and Chiefs.
Two players who have hardly play for the Bulls this season in Willie Wepener and Deon Stegmann have both been included.
However Stegmann, who was injured his hamstring in week two against the Cheetahs, will have to pass a fitness test before travelling.
Should he not make it, his rehabilitation will continue in Pretoria and he will then join the squad as soon as he is passed fit.
Wepener is suffering from Gamsay Hunt syndrome, a virus that attacked his facial muscles, but his condition has improved to such an extent that he will be able to tour with the team.
He last played against the Reds in week four.
Bulls coach Frans Ludeke said the four matches will determine their season.
"We are in a good spot at the moment. We have no serious injury concerns and will travel with some momentum after the last win over the Brumbies.
"The bye was also a good one and the players were able to refresh mentally.
"We will need to win on the road though if we want to stay in the hunt for the play-off position."
The Bulls play the following fixtures on tour.
May 4th: Rebels, AAMI Park, Melbourne
May 11th: Waratahs, Sydney Football Stadium, Sydney
May 19th: Highlanders, Forsyth Barr Stadium, Dunedin
May 25th: Chiefs, Waikato Stadium, Hamilton
The Bulls touring squad is:
Zane Kirchner, Akona Ndungane, Bjorn Basson, JJ Engelbrecht, Wynand Olivier, Johann Sadie, Francois Venter, Louis Fouché, Morné Steyn, Jano Vermaak, Francois Hougaard, Pierre Spies (c), Arno Botha, Deon Stegmann, Jacques Potgieter, CJ Stander, Juandré Kruger, Wilhelm Steenkamp, Flip van der Merwe, Werner Kruger, Dean Greyling, Frik Kirsten, Dawie Steyn, Chiliboy Ralepelle, Bongi Mbonambi, Willie Wepener.