Williams missed last week's home match against the Cheetahs with concussion, but has been fully cleared to play in South Africa in the match at Newlands.
Fellow All Black Ofa Tu'ungafasi gets his second start of the season after his man-of-the-match performance coming on for the injured Pauliasi Manu in the win over the Cheetahs at Eden Park last weekend.
The only other change from the starting line-up that beat the Cheetahs sees Gerard Cowley-Tuioti return to partner fellow in-form lock Scott Scrafton with All Black Patrick Tuipulotu to add real thrust off the bench.
Piers Francis, who came off with injury at half-time last weekend, has recovered sufficiently to be named to start at flyhalf with Bryn Gatland returning to the squad in the reserves.
Melani Nanai, who has bagged five tries this season, retains his spot at fullback with Michael Collins to come off the bench.
Head coach Tana Umaga said the team had settled well after the long flight from New Zealand and were looking forward to what he expects will be a tough challenge against the Stormers.
Players not available because of injury include Jerome Kaino (knee), Pauliasi Manu (calf), Matt Moulds (knee), Ihaia West (ankle) and Jimmy Tupou (hamstring).
Stephen Perofeta (ankle) has successfully returned to action and will complete his return to play with a second club game this week.
Blues: 15 Melani Nanai, 14 Matt Duffie, 13 George Moala, 12 Sonny Bill Williams, 11 Rieko Ioane, 10 Piers Francis, 9 Augustine Pulu, 8 Akira Ioane, 7 Blake Gibson, 6 Steven Luatua, 5 Scott Scrafton, 4 Gerard Cowley-Tuioti, 3 Charlie Faumuina, 2 James Parsons (captain), 1 Ofa Tu'ungafasi.
Replacements: 16 Hame Faiva, 17 Alex Hodgman, 18 Sione Mafileo, 19 Patrick Tuipulotu, 20 Kara Pryor, 21 Sam Nock, 22 Bryn Gatland, 23 Michael Collins.
Date: Friday, May 19
Venue: Newlands, Cape Town
Kick-off: 19.00 (17.00 GMT; 05.00 NZ time, Saturday, May 20)
Referee: Jaco van Heerden
Assistant referees: Marius van der Westhuizen, Cwengile Jadezweni
TMO: Shaun Veldsman
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