Castillo elected free agency Sunday.
Castillo cleared waivers after the Twins designated him for assignment Wednesday, and rather than sticking around in the Minnesota organization as pitching depth at Triple-A St. Paul, the 30-year-old will look to find work elsewhere. Prior to being pushed off the 40-man roster, Castillo made five relief appearances for Minnesota and gave up two earned runs on five hits and seven walks over seven innings.