Gattis batted .263 with 22 home runs and 52 RBIs last season as the Braves' primary catcher. He also had a team-best .493 slugging percentage.
Justin Upton, who had the second-highest slugging percentage on the team last season, was also traded this winter.
Foltynewicz was ranked as the No. 43 prospect in baseball prior to last season by Baseball Prospectus. He was called up by the Astros on Aug. 1 and made 16 appearances out of the bullpen. He allowed 23 hits and struck out 14 batters in 18.2 innings.
Foltynewicz is a righthanded power pitcher whose fastball is capable of reaching 100 mph. His average fastball velocity was 96.8 mph last season, according to PITCHf/x.
- Dan Gartland