Dansby Swanson has become an absolute force in the middle of the Braves lineup. Unlike the other two players listed in this article, he is set to hit free agency in the very near future. He will be an Unrestricted Free Agent after this year, and I am sure the Braves are already in discussions with his reps.
Swanson was a first overall pick by the Arizona Diamondbacks in the 2015 draft. He was traded that same year to Atlanta in a famous trade that saw the Diamondbacks receiving Shelby Miller. It is neither here nor there, but that trade did not work out for Arizona.
Swanson is the WAR leader for the position players on the Braves currently with 5.2. He is a defensive wizard at shortstop, with a 14.5 defensive score on FanGraphs, which is the highest on the team. In 502 at-bats, Swanson has a .808 OPS, and a .294 batting average.
The concerning part for the Braves has to be the fact that he has never been this good to this point. His highest WAR season besides this one was last year with a 3.4. As far as wRC+, he was considered barely a below average hitter last year with a 98. With Swanson, the Braves know they are getting top notch defense, but the bat is up for debate.