"I wouldn't be at all surprised to see one of them taken into the Rugby Championship, not necessarily to play but to look at them, to see how they might handle it.
"One I don't think anyone is talking about is one of the (Super Rugby) stars Hayden Parker.
"With the Sunwolves going out of the competition next year, I'm not sure of his contract status. A player like him could come back and play Mitre 10 Cup, and take a Super Rugby contract next year.
"He is experienced and one of the best goalkickers around, brave. He is a bit more experienced, and you need experience in the World Cup.
"I don't see them picking a young, third No. 10 for the sake of filling a gap."
The 28-year-old Parker, who played for New Zealand under-20s, emerged with Otago and has played about 50 Super Rugby games for the Highlanders and Sunwolves.
On Aaron Cruden, Hart said the former test player was not in the best form in Europe. He suspected any sudden return home would have to be driven by the Chiefs, and the All Blacks could evaluate Cruden from there.
Hart also said utility Jordie Barrett is capable of covering for the loss of Damian McKenzie as the third first five-eighth. He said Barrett, more of an outside back, "does have the capacity to fill the gap".
There would now be major attention on the fitness of Beauden Barrett and Richie Mo'unga, he added.
"You wouldn't want another injury - if we lost another 10 it would be a serious problem."
