I think he'll enter the race. Would be surprised if he doesn't at this point tbh.
While once he does, if he does, he's definitely the favorite in the primary, I wouldn't say he's a guarantee to win it. Gary Black is a solid candidate because of Georgia's agriculture business. Probably has the better chance in the general election too, IMHO. I don't think Herschel's UGA legacy works in this state as a whole (it may very well in the primary though). Even if you want to say Georgia is not a purple state, that doesn't make Georgia similar to Alabama outside of rural Georgia...
As a bonus, I think the Vernon Jones primary of Brian Kemp ends up failing. While Kemp isn't very popular for anybody in the state, I think he gets saved in the primary by country club type Republicans.