GOP frontrunner Donald Trump doesn't come to metro Atlanta until Saturday.

But he started warming up his Georgia constituents Thursday by attacking one of the biggest names in Peach State conservative circles.

Trump launched a Twitter attack on Erick Erickson of RedState. Erickson fired back on his WSB Radio show.

The two have been at war since August when Erickson "disinvited" Trump to the RedState Gathering, which attended by leading Republican candidates for president. Erickson shunned Trump after Trump made derogatory comments about a female television debate host.

Trump holds a major campaign rally Saturday in Norcross, which is expected to draw thousands.

Trump tweeted Thursday that Erickson had been "fired like a dog" from RedState, the conservative  website he founded over a decade ago.

Erickson, a radio host and Fox News contributor, announced earlier this week that he was leaving RedState, because the site  had been acquired by Salem Communications, which competes with Erickson's current radio broadcaster, Cox Media Group. CMG is a division of Cox Enterprises, which also owns The Atlanta Journal-Constitution.

Trump didn't buy that explanation: "If you read his tweets, you'll understand why [he was fired]," Trump wrote. "[He] just doesn't have IT!"

Erickson shot back by making light of the attack: "Wow. Donald Trump lives in a universe where even dogs are fired," wrote, later adding that Trump had his facts wrong.

Erickson, who once held local office in the Macon area, later tweeted: "A difference between Donald Trump and me: I got elected to office and he never will."