The Yankees will face an old friend during the series opener against the A’s in Sacramento on Friday.  Right-hander Luis Severino will take the mound against his former team after one of his best outings of the season last Thursday, though the matchup will come at a venue that has already been a source of frustration for the veteran starter. Severino has talked openly about not liking pitching at the A’s temporary home, Sutter Health Park, saying a year ago that “it’s tough to pitch here” and