Marshall Suckling injured his knee in a pre-season warm-up match and is out for the rest of the season.
Buxton Popoali'i then strained his hamstring in last Sunday's game against Bay of Plenty, and is not available to play in the match in Hamilton.
Now, Kieran Moffat is in doubt for the match which also doubles as a Ranfurly Shield challenge.
Moffat has injured his calf, picking up a bad bruise to it in the game on Sunday, and did not take part in training yesterday.
He has been bracketed with Matt Faddes in the side named to take on Waikato.
A decision on whether Moffat, who made his Otago debut on Sunday, will play, will be made tomorrow. The only change to the starting side is the inclusion of youngster Fa'asiu Fuatai, who comes in on the left wing to replace the electric Popoali'i.
Alhough he has played the majority of his rugby in the midfield, Fuatai played on the wing for the New Zealand Colts at the world junior championships in June.
Popoali'i could have played at a stretch but there was a strong possibility he could have done some real damage to the hamstring.
It is hoped to have him back for the following match against Hawkes Bay at Forsyth Barr Stadium on September 1.
Jayden Spence, who is coming back from concussion, comes on to the reserves bench.
Otago coach Tony Brown has decided to leave explosive loose forward TJ Ioane on the bench.
He has stuck with his starting loose forward trio of Gareth Evans, Lee Allan and captain Paul Grant.
Experienced prop Tama Tuirirangi comes on to the bench, with Aki Seiuli left out of the 22-man squad.
Hooker Liam Coltman, who spent the past couple of days in the All Black camp as the first ''apprentice'' hooker attached to the national side, will link up with the team in Hamilton tomorrow.
Waikato is due to name its team today.
It will be Otago's 23rd attempt, going back 56 years, to win the Ranfurly Shield.
The Otago side last had a challenge in 2010, against Southland.
Its most recent challenge in Hamilton was in 1999 when it lost 29-17.
Otago has not won in Hamilton since 1995. It has played Waikato 10 times in the northern city since and lost every time.
Otago side
To play Waikato
Tony Ensor, Matt Faddes or Kieran Moffat, Michael Collins, Peter Breen, Fa'asiu Fuatai, Hayden Parker, Fumiaki Tanaka, Paul Grant (captain), Lee Allan, Gareth Evans, Tom Franklin, Tom Donnelly, Scott Manson, Liam Coltman, Craig Millar. Reserves: Sam Anderson-Heather, Tama Tuirirangi, Charlie O'Connell, TJ Ioane, Willis Scott, Josh Renton, Jayden Spence.
