Springbok to miss Bulls' Newlands trip
The three-time champions face the Stormers in a traditional north-south derby in the opening round of the 2017 Super Rugby season.
Serfontein, Martin Dreyer and Shaun Adendorff will not be available for selection for the encounter with the Stormers.
Bulls team doctor Herman Rossouw said it was decided to give Serfontein another week in rehabilitation, while Dreyer and Adendorff are carrying minor niggles.
All three players are expected to be fit for next week's trip to Bloemfontein and a Round Two encounter with the Cheetahs.
Serfontein, who missed the second half of 2016 after undergoing surgery for a scaphoid fracture, is struggling with a back strain.
The 23-year-old centre, who has made 26 Test appearances since his Bok debut in 2013, is a key player in the Bulls' campaign this year.
Roelof Smit is making steady progress, after he underwent surgery for the torn pectoral muscle injury he sustained while playing for the Boks against the Barbarians in November.
He is expected to be ready for selection towards the end of April.
Conraad van Vuuren injured his ankle early in the pre-season and has undergone surgery.
He will only be available for selection in six weeks' time.
Jannes Kirsten (shoulder surgery), Arno Botha (shoulder surgery) and Adriaan Strauss (back surgery) are making steady progress.
They will continue to train with the Bulls' rehabilitation squad for a further three weeks, before joining the squad for contact sessions.
