What happened: The Athletics are hiring Cam Castro away from the World Series champion Milwaukee Brewers to serve as general manager. Castro will step into the role under new president of baseball operations Taylor Smith.

Why it matters: The hire pairs Smith with an executive fresh off Milwaukee's title run, injecting championship pedigree into the Athletics' front office. Castro will help oversee roster construction and player development as the organization reshapes its leadership hierarchy.

What to watch: The Athletics are expected to finalize their front-office structure ahead of the winter meetings as Castro and Smith prepare for offseason roster moves.