Reached by phone at home on Sunday, Mr. Arpaio said that he was not sure why Mr. Trump was thinking of the pardon, and that he had not talked to the president since around Thanksgiving, when Mr. Trump called to ask about the health of Mr. Arpaio’s wife. But Mr. Arpaio would not say whether he had talked to the Trump campaign or White House about the visit Tuesday, or whether he had made formal plans with them to make an appearance.

“I did not have any input. I don’t know what the official comment will be,” Mr. Arpaio said. “He has a mind of his own. We all know that, don’t we?”

Mr. Arpaio had appeared surprised — then flattered — when he learned of Mr. Trump’s interest in the pardon. He told Fox News last Monday that he “would never ask him for a pardon, especially if it causes heat.”

But he said on Sunday that he was “honored by the potential pardon” and would accept it.

Mr. Trump has long admired Mr. Arpaio for what he sees as his no-nonsense posturing against undocumented immigrants.

“Is there anyone in local law enforcement who has done more to crack down on illegal immigration than Sheriff Joe?” Mr. Trump asked during the Aug. 13 Fox News interview. “He has protected people from crimes and saved lives. He doesn’t deserve to be treated this way.”