If the Braves do add an ace they will have Julio Teheran and Mike Foltynewicz and a large combination of young arms competing for the 5th spot in the rotation leaving either the 3rd or 4th rotation spot open.
Despite his age Rich Hill could fill that position perfectly. When he is healthy he is a solid veteran starter that could keep the Braves in games and has shown his ability to pitch at an ace-like level. The problem for Hill is his tendency to get hurt.
In this certain case however that may not be a horrible thing if he accepts a reasonable deal. A possible injury would be backed up by some of the best young arms that any minor league system has to offer. Rich Hill could prove his track record wrong as well with a guaranteed rotation spot and remain healthy for a complete season.
The one pitfall for the Braves here is the fact that Hill is the best starter out there in a very thin market. If that makes his price more than his talent level deserves the Braves could look at other free agent options. The market is full of veteran free agent pitchers, the problem is finding one who can keep the Braves in games and help the young starters.