Answer: B.J. Upton
The first Upton brother to arrive in Atlanta was that of B.J. Upton who signed in November of 2012. From the start Upton failed to provide the elite speed and power combo he showcased in Tampa for eight seasons.
Things started rough and never improved for B.J. until ultimately he was dealt in the Craig Kimbrel to San Diego trade. Although that trade didn't bring back immediate help, it did bring a comp pick to Atlanta, one that would later turn into the selection of current star third baseman Austin Riley.
All in all his career numbers weren't too bad, as Upton hit 164 homers, stole 300 bases, had a career 98 wRC+, and was worth 24.7 fWAR across his 12 seasons in baseball.