After leaving Iowa Wesleyan, Lawson began playing professional baseball with the Keokuk Indians in Keokuk, Iowa. He did not make it in Keokuk and was demoted to a club in Decorah, Iowa. While playing for Decorah, he signed with a scout for the Cleveland Indians. The Indians assigned him the Terre Haute Tots in the Three-I League. In two seasons with Terre Haute, he compiled an 8–4 record in 1929 and a 14–7 record in 1930. Wildness continued to be a problem for Lawson while with Terre Haute.