Yoshinobu Yamamoto struck out three batters in two scoreless innings in a dazzling pre-season debut Wednesday for the Los Angeles Dodgers, who have bet big that the 25-year-old Japanese star will be a Major League Baseball ace.In the second inning, Yamamoto struck out Nathaniel Lowe, induced a fly out from Jonah Heim and, finally, struck out Leody Taveras -- who went down swinging on a 91 mph splitter.