Lions captain Whiteley, 28, had been expected to miss the entire play-off series after hurting his shoulder playing for South Africa against Ireland last month.
Doctors ruled him out for six weeks but Whiteley is on the verge of an early recall following a quick recovery.
"We are positive he’ll be okay," assistant coach Swys de Bruin told local reporters. It would be another gamble by coach John Ackermann, who fielded a second string team in the final game of the regular season away against the Jaguares in Buenos Aires last Saturday and lost.
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(Reporting by Mark Gleeson in Cape Town; Editing by Amlan Chakraborty)
