Santo For Three More Years

Ron Santo is a Chicago Cub legend. He played for the Cubs from 1960 to 1973 playing third base. Then he joined WGN Radio to do the Chicago Cubs broadcasts on the radio in 1990. Ron Santo was one great player, but he was never a All-star broadcaster like he was on the field. That is why he is in Game Of Inches
"The Worst Sports Announcer In The World Competition." He just signed a three-year extension. He will turn 70 in February, and has showed signs of confusion a few times throughout games the past few seasons. Santo loves the Cubs and shows it in every broadcast.

I read about his extension on the Cubs website. If you look at the subtitle of the article under the title where it says "Analyst Santo signs three-year extension" you will see it says "Former Cubs DH entering 21st season in radio booth". To my knowledge Santo was third basemen for the Chicago Cubs his entire Cubs career. It would be hard for him to DH with the Cubs in the National League! Santo did play for one year with the White Sox after his Cubs career ended and I believe he was a DH with them, but this subtitle says "Former Cubs DH entering 21st season in radio booth" so how was he a Cubs DH?