The Counterfeit Tackle — Matt Christopher

Buzz and Corky may be identical twins, but they are not very much alike. Corky, outgoing and popular, plays tackle on the Otters football team. Buzz, the school chess champion, is quiet and reserved. Corky is surprised when Buzz offers to substitute for him as tackle one day so that Corky can go see a professional game. And Buzz is surprised to discover that he likes playing football and being part of the gang. But changing places leads to more complications than the boys ever imagined. Will they be able to keep their secret?