The Dodgers have one of the best farm systems in baseball known both for its talent and depth. Unfortunately that depth is only at certain spots. Catcher is the immediate position that comes to mind, followed by the outfield and pitching. One position group lacking is the middle infield.
So that means the answer to the second base question will likely be someone who is already on the big league roster.
The three prime candidates for the spot are Enrique Hernandez, Austin Barnes, or Chris Taylor. Another dark horse candidate is Jake Peter who lit it up in spring training.