SA Rugby's deputy president Mike Stofile, who is set to challenge Oregan Hoskins for the presidency at the body's elections next month, was upset the announcement was made without consultation with SA Rugby's hierarchy and told the Cape Times he will "get to the bottom of this."
He said: "I do not know who appointed John Smit as Springbok captain. Whoever made this appointment did it without the leadership of rugby being involved.
"The Super 14 has also just started, so it is too early to choose a captain now.
"If I was the coach, I would first assemble the squad and assess them. Once I have done that, I will pick the captain from there."
De Villiers made the decision after he had met with Smit's club Clermond Auvergne last week in France.