The Reds promoted Stewart from Single-A Daytona to High-A Dayton on Aug. 8.
The 19-year-old third baseman earned the bump on to Dayton after showing some decent pop (10 home runs and 19 doubles) and exceptional plate discipline (66 walks against 59 strikeouts) over his 387 plate appearances in the Florida State League. Since joining the High-A club, Stewart is slashing .277/.386/.319 through 12 games.