Sunwolves face Kings without Viljoen
The 33-year-old fullback will be replaced by Shota Emi.
The other changes in the backline see the halfback pairing of Keisuke Uchida and Hikaru Tamura replaced by Fumiaki Tanaka and Hayden Cripps.
In the pack, South African Willie Britz has retained the No.8 jersey, but Shokei Kin will start as openside flank in place of Malgene Ilaua in the starting XV.
Sunwolves: 15 Shota Emi, 14 Takaaki Nakazuru, 13 Timothy Lafaele, 12 Derek Carpenter, 11 Kenki Fukuoka, 10 Hayden Cripps, 9 Fumiaki Tanaka, 8 Willie Britz, 7 Shokei Kin, 6 Ed Quirk, 5 Sam Wykes, 4 Liaki Moli, 3 Heiichiro Ito, 2 Shota Horie, 1 Masataka Mikami
Replacements: 16 Takeshi Hino, 17 Koki Yamamoto, 18 Takuma Asahara, 19 Kotaro Yatabe, 20 Shuhei Matsuhashi, 21 Keisuke Uchida, 22 Will Tupou, 23 Jamie-Jerry Taulagi
Date: Saturday, March 4
Venue: Singapore National Stadium, Singapore
Kick-off: 18:55 local (10:55 GMT)
Referee: Marius van der Westhuizen
Assistant Referees: Egon Seconds, Akihisa Aso
TMO: Minoru Fuji
