LOS ANGELES — The Mets found three heroes in three games over the weekend in a sweep of the Oakland Athletics and that’s exactly what they were looking for. With nine guys on the field and eight more in the bullpen, the Mets want to emphasize playing a solid team game and not being overly reliant on one big bat or one big arm. Baseball can often be an individual sport disguised as a team sport but games are won and lost as a team.