No matter how many candidates sign up, however, the center of gravity in the race may well be President Trump, who won the state by a whopping 30 points in November.
With a healthy campaign war chest and a solid record of convincing wins in the "purple" Sixth District, Barr is well positioned to be among the frontrunners in the primary.
But with former gubernatorial candidate and McConnell protégé Daniel Cameron jumping in the race just minutes after the long-serving senator's announcement that he would not seek another term, it wasn't long before the jabs started. The initial sparks showed candidates (and anticipated candidates) would waste no time angling for a Trump endorsement.
Barr has said the state should have a senator who backs the president — seeming to distance himself from McConnell, who has parted company with Trump on tariffs, foreign policy, and some nominations.
"I think the people of Kentucky deserve, number one, a US Senator that supports this president," Barr told KET's Renee Shaw in February.
"And Mitch McConnell, you think, does not?" she responded.
"Well, in some cases, he does. In some cases, he doesn't," Barr replied. "I'm my own man."
A Barr spokesperson also said Cameron "embarrassed" Trump by losing to Democratic Gov. Andy Beshear in 2023.
Asked about the gravitation away from McConnell in his party's Senate race during the legislative session, Senate President Robert Stivers said it's not a tack he would take.
"If I were to get into a primary like this, I would not speak ill of any of my Republican opponents. That's their choice," he said. "As to Sen. McConnell, I believe he's owed a certain amount of respect. I do not agree with the tactic of dissing — I don't say distancing — dissing Sen. McConnell."
Meanwhile, Cameron's team has pointed to early polling showing their candidate leading and sought to paint Barr as a DC insider.
Barr's announcement is set for Tuesday evening in Richmond.