Complex sentence: Although several offers were put forward by Philadelphia interests, American League president Will Harridge was convinced that the team could never be viable in Philadelphia, and the only way to resolve the "Philadelphia problem" was to move the Athletics elsewhere.
Split into simpler sentences: Although several offers were put forward by Philadelphia interests, American League president Will Harridge was convinced that the team could never be viable in Philadelphia. As a result, Harridge had come to believe that the only way to resolve the "Philadelphia problem" was to move the Athletics elsewhere.