"He has gone (to the US from Mumbai) for regular health checkup," the sources said.
Last week, the top star had left for Mumbai from Chennai to take part in the shooting of "Kaala Karikalan", directed by Pa Ranjith.
The 66-year-old actor recently gave indications that he was holding discussions on entering politics.
"I have not denied it. We are discussing and yet to take a decison. Once I take a decision, I will inform you," the Kabali star had said.
The shooting for "Kaala Karikalan" was going on at a brisk pace in Mumbai over the last few days.
Rajinikanth, who had met his fans in May, had asked them to "prepare for war", hinting that he might consider entering politics.