The only Ron Santo cards in my collection that show him in a double-knit uniform all use this one picture. It has to be from 1972-73, his last two seasons with the Cubs before being traded to the White Sox. The stripe of the sleeve narrows it down to 1972. My first thought here was that no-one looked good in these tight fitting uniforms. Then I remembered the Cardinals and guys like Ozzie Smith and Willie McGee. So, let me say instead that meatier guys late in their careers didn't look so good. No offense, Ron.
(click to enlarge)