Centre/winger Filipo Daugunu was also released to join tighthead Tupou in Toutai Kefu's First Nations squad for the clash against Andy Farrell's Lions in Melbourne on Tuesday.
Both missed out on selection for the Wallabies' series-opener against the Lions in Brisbane on Saturday.
Schmidt opted for Allan Alaalatoa as his starting tighthead with New South Wales prop Tom Robertson earning a spot on the bench.
It is the second time Tupou has been released from the Wallabies having missed out on the warm-up test against Fiji to play for his Super Rugby side NSW Waratahs in their tour match defeat by the Lions in Sydney.
Former Wallabies number eight Kefu told Reuters he was glad for the reinforcements as his squad prepares for a Lions outfit that humiliated the invitational Australia-New Zealand XV 48-0 in Adelaide last Saturday.
"We've got a decent squad, actually. I'm pretty happy with my forward pack," he said.
"I think our locks are world class. I'm sure they'll have a good game and come in the reckoning for Wallabies honours."
Kefu has former Wallabies locks Lukhan Salakaia-Loto and Darcy Swain along with Queensland Reds' Seru Uru and Fijian Drua's Mesake Vocevoce as second row options.
Kefu, who played in the 2-1 series win over the Lions in 2001, was in the coaches' box for the Australia-New Zealand XV thrashing in Adelaide.
He said his squad would have their work cut out containing the Lions after having only a few sessions together to prepare for them.
"They've looked pretty good," he said of the Lions, who are undefeated in the Australian tour.
"Those provincial teams have been together a lot longer than us and they struggled somewhat.
"It's going to be a tough challenge."