The man who pulled Shohei Ohtani's 50th home run ball from a scrum in the stands of LoanDepot Park on Thursday afternoon is about to be a whole lot richer ... 'cause, according to auction experts, the keepsake is worth a small fortune. David Kohler, president of SCP Auctions tell TMZ Sports ... based on their initial evaluations -- the baseball that Ohtani socked over the left field wall during the Dodgers' blowout win over the Marlins will likely sell for over $300,000 on an auction block.