Shohei Ohtani’s 50th home run ball that made him the first Major League Baseball player to achieve 50 home runs and 50 stolen bases in a single season will be put up for auction starting Friday, a U.S. auction house said. The starting bid will be set at $500,000, with an option to purchase it privately for $4.5 million if bidding does not exceed $3 million by Oct. 9, Goldin Auctions said Wednesday. Ohtani hit the milestone home run on Sept. 19 against the Miami Marlins, ending the night with a 51-51 record as the Los Angeles Dodgers clinched a playoff berth, a first for Ohtani in MLB. Goldin’s…