A Quinnipiac University poll released Wednesday showed Miller capturing 1 percent in the Republican primary. At 39 percent, Rep. Connie Mack (R-Fla.) is the clear front-runner for the GOP nomination, and the only candidate to top 6 percent.
But appreciative as he might be for Miller's support for his tax plan, Cain has no current plans to return the favor by endorsing the Florida businessman.
"Mr. Cain is like a father, and now he wants to adopt children, so to speak. He's saying that kind of tongue-and-cheek, and some people may interpret that" as an endorsement, the aide said. "At this point, that's not in the stars."
What could be in the stars — according to Cain's team — are more federal candidates getting behind 9-9-9.
"I'll tip my hand on this one: Pete Hoekstra in Michigan is in the works to do the same," the aide said.
Hoekstra, a former Republican congressman, is the front-runner in the race to unseat Sen. Debbie Stabenow (D-Mich.).
A spokeswoman for Hoekstra did not respond to a message left Wednesday evening seeking comment.
—Cameron Joseph contributed.