Thatcher was granted his release from the Indians on Sunday, MLB.com's Jordan Bastian reports.
Rather than sticking with the Indians as organizational depth at Triple-A Columbus after failing to win a roster spot with the big club, Thatcher decided he was better served pursuing an opportunity with another team. The left-hander made 43 appearances for the Astros in 2015, logging a 3.18 ERA, 1.54 WHIP, and 26:12 K:BB ratio over 22.2 innings.