SAN FRANCISCO — When it comes to old school versus new, there isn’t a more polarizing player in today’s game than Luis Arráez. The veteran infielder is a three-time batting champion who hit .292 last year in what was considered a down year for the San Diego Padres. By some traditional measures — All-Star appearances, Silver Sluggers, hits — his career has at times been on a path to Cooperstown. While picking up all those hits, including a league-leading total last year, he virtually never strikes out.Arráez also rates as a poor defender by all modern analytics and the eye test. He might bat .300 just about every year, but by wRC+, he was roughly a league-average hitter last season. He ranked in the first percentile last year in hard-hit percentage and bat speed. His sprint speed puts him in the bottom quarter of the league.What do you see when you watch Arráez play? That might vary greatly depending on how you view the game. But it’s clear what the Giants see. Arráez is their new second baseman, and while it’s an imperfect fit in a lot of ways, it also is one that makes a lot of sense given...