David Ross was certainly an unconventional choice for Cubs manager for the next three years (at least!), even as he was a popular selection by Theo & Co.
Ross has no managerial experience. There have been several managers hired with no previous credentials in recent years, with mixed results. Robin Ventura did all right for a year or so with the White Sox, then the team collapsed and he was let go. On the other hand, Aaron Boone stepped right in with the Yankees and did a spectacular job mixing and matching players to replace a large part of his roster who were injured.