The Atlanta Braves were already happy about the Chris Sale trade if we are being honest. In giving up Vaughn Grissom who did not seem to have a path to playing time in Atlanta, the Braves got a future Cy Young winner and a guy who remains the ace of their staff today. Considering they only had to pay part of his contract as well, that is a massive win.
Unfortunately for Grissom, his time in Boston has not gone nearly as well. While he has put up solid to good numbers in the minor leagues with the Red Sox, his relationship with the team was frayed due to the lack of opportunities he has gotten (and, in his mind, deserves) and a divorce became inevitable.