According to MLBTradeRumors.com, the A's have traded Matt Murton to the Rockies for infielder Corey Wimberly. Wimberly played primarily second base for the Colorado system and he ranked as the 26th best prospect according to Baseball America.

I've never heard of the guy. He seems fast, though. And Matt Murton wasn't really in the discussion of making the team as an outfielder. After Holliday, Sweeney, Cust, Buck, Denorfia, Cunningham, Davis, etc... 

More details if any more come out.