"I'm not necessarily saying I saw it coming," Bradley said. "I wanted to be here as long as I could, and I think I did that. I understand being sent down for some things I need to work on and get better at. It's part of it, so go take care of business and get back up here."
Bradley, ranked by MLB.com as the game's top pitching prospect, will start the 2014 season with Triple-A Reno.
"We put a lot on him, we asked him to try a lot of things," manager Kirk Gibson said. "He tried them. Overall, I thought that the right thing is to send him back to the Minor Leagues and finish off. We want him to stay here when he comes. He's just got some things to simplify and finish off. He's close."
The biggest things Bradley needs to work on is his fastball command and the improvement of his changeup.
"I think I can compete there now," Bradley said of the big leagues. "That's just the way I am, but at the same time, I look at what I did this spring and there's still some things I need to polish out and get better at. I think this is what this is all about, go down there and prove to them that I can do that and then everything will work out."
Steve Gilbert is a reporter for MLB.com. Read his blog, Inside the D-backs, and follow him on Twitter @SteveGilbertMLB. This story was not subject to the approval of Major League Baseball or its clubs.