Injuries forced Sunwolves coach Jamie Joseph to make a number of changes Thursday to his Super Rugby side for this weekend's visit by the Melbourne Rebels.

Kazuki Himeno (hip), Lomano Lemeki (hand), Grant Hattingh (chest) and Jaba Bregvadze (knee) all picked up knocks last week against the Brumbies that will keep them out for a week or so. Hosea Saumaki is also out after twisting a knee in training, while Jason Emery underwent surgery Thursday for a broken thumb.

"There has been a lot of criticism about why we have so many players, particularly foreign players and this is why," Joseph said of the early season injury crisis.

But such is the improved depth of the squad that Joseph can call upon the likes of Michael Leitch, Akihito Yamada and Harumichi Tatekawa for Saturday's game at Tokyo's Prince Chichibu Memorial Rugby Ground.

"We've had a few injuries from the first match and it's compounded by already having a few in the same position, particularly the outside backs," said Joseph. "The only thing that is consistent in Super Rugby is we are going to get injuries."

Overall, there are three changes and one positional switch in both the forwards and the backs.

Craig Millar replaces Keita Inagaki at loosehead prop and partners Shota Horie and Koo Ji Won in the front row.

Willie Britz moves from No. 8 to the second row where he will line up with Sam Wykes, while in the back row, Leitch joins Lappies Labuschagne and Ed Quirk, who has been promoted from the bench.

"I wanted to give Leitch a rest but we lost Himeno and all our locks so we had to bring him in," Joseph said.

Yutaka Nagare will once again lead the side from scrumhalf and he will have Hayden Parker outside him with Robbie Robinson moving from 10 to 15.

Ryoto Nakamura and Timothy Lafaele keep their spots in the centers with Yamada and Will Tupou joining Robinson in the back three.

"The Rebels have a big backline so we need to make sure we can compete in the physical side of the game. They also kick a lot and Willie is good under the high ball," Joseph said of the inclusion of Tupou, who missed much of the Top League season through injury.

Joining Inagaki on the bench to supply cover for the forwards are Atsushi Sakate, Asaeli Ai Valu, James Moore and Rio Olympian Yoshitaka Tokunaga.

Tatekawa, Fumiaki Tanaka and debutant Ryuji Noguchi are the reserve backs.

"Tatekawa is a leader and we lacked a bit of leadership in the last 10 minutes last week," Joseph said of the 32-25 loss to the Brumbies.