"I guess it's a little unexpected, but I feel pretty good," he said. "I had some pretty solid outings in Triple-A that I felt good about. I guess they felt I was ready to come back."
Porter described Fields' outings with the RedHawks as "dominating." The Astros had so much confidence in Fields the first month of the season that he was in the mix of relievers who were closing games. Porter said the Astros wanted Fields to relax.
"That's one of the things we talked to him about before he left," he said. "You see the power arm, you see the breaking stuff. But sometimes the game can speed up on you at this level. Being able to slow the game down and relax and make pitches is one of the big aspects of being a good Major League pitcher and being able to play to your potential."
Brian McTaggart is a reporter for MLB.com and writes an MLBlog, Tag's Lines. Follow @brianmctaggart on Twitter. This story was not subject to the approval of Major League Baseball or its clubs.