Major League clubs often add players to their respective 40-man rosters around this time of year to protect eligible players from being selected in the upcoming Rule 5 Draft.
Chapman enjoyed his best professional season while posting a 2.50 ERA and recording 77 strikeouts in 68 1/3 combined innings with Double-A Mississippi and Triple-A Gwinnett. The 24-year-old right-hander limited opponents to a .164 batting average and recorded 2.48 strikeouts per walk.
Hoover produced a 2.48 ERA and limited opponents to a .203 batting average in 31 games (12 starts) with Mississippi this year. The 24-year-old right-hander limited opponents to a .171 batting average in 12 appearances (two starts) after earning a late-season promotion to Gwinnett.
Avilan posted a 4.57 ERA in 36 appearances (13 starts) with Mississippi this year. The 22-year-old left-hander was utilized as a starting pitcher during the season's final two months. As a starter, he was 3-4 with a 3.82 ERA.
The Braves now have 36 players on their 40-man roster.
Mark Bowman is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.