"Hey Rubio, when you get back to Iowa, I'll be waiting for you Rubio," said the boy, who was identified as Brody Dill by the Des Moines Register.
In the video his uncle posted on Twitter, Dill looks determined in the video, gripping a football and wearing sporty clothes.
He got bonked in the head in Iowa on Monday when Rubio held a family picnic for family, friends and supporters.
Video and images of his throw went totally viral soon after.
Rubio joked about his terrible throw, tweeting: "The QB always gets the blame.”
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