What makes an ace? The pitching parameters that define that strict shorthand run longer than a doubleheader, because every eye sees something different on the mound. He is something more than a team’s best pitcher. You know it when you see it. Colorado right-hander Jon Gray on Wednesday pitched in his 50th career start, a miniature milestone in a still-budding career filled with the potential and expectation of a high draft pick and a rocket arm.