Nathan Deal's top aide delivered quite a message at the Georgia Chamber's annual conference last week: If you're a Republican and decide to run against the Georgia's current governor in 2018, you're going to get hurt.

The message from chief of staff Chris Riley was directed at Republicans already lining up to replace him, and took the cryptic form of a football metaphor. Imagine a wide receiver running a route over the middle, Riley said. Now imagine the free safety on defense, ready to deck him. Hard.

Riley didn't say who that free safety would be. Just that he'd be there.

By and large, three GOP contenders -- Lt. Gov. Casey Cagle, Secretary of State Brian Kemp and state Sen. Hunter Hill of Atlanta -- have had nice things to say about Deal early in the campaign. State Sen. Michael Williams, a fourth candidate in the race, has taken the opposite stance: He's running against a "crony" establishment.

In an interview Tuesday, Cagle said he would make the case that Georgians should be "very proud" of the achievements of the last eight years.

"When you look at Georgia, the No. 1 state to do business in four years running, when you look at the governor's legacy in criminal justice, along with what we've been able to do with the workforce and college and career academies ... we're prepared obviously to defend that record."

Later Tuesday, Williams released a statement that his campaign was "just getting started."

“It’s clear the establishment is afraid of our message getting out," the campaign said. "They want to shut us down now because they know we are gaining ground."

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Another candidate who is not likely to win kudos from Gov. Nathan Deal's staff: State Sen. Josh McKoon of Columbus.

He's told supporters he's not likely to run for governor, but may join the already-crowded field for secretary of state. He's said to be considering entering the race over the next few weeks, and will make up his mind likely after the fundraising deadline at the end of the month.

At least three Republicans are in the contest: State Reps. Buzz Brockway of Lawrenceville and Brad Raffensperger of Johns Creek, and Alpharetta Mayor David Belle Isle. Democrat R.J. Hadley of Rockdale County has also filed the necessary paperwork.