Complex sentence: National League president Chub Feeney spoke to Mets' management and threatened the Mets with a forfeit, Yogi Berra, Willie Mays, Tom Seaver, Rusty Staub and Cleon Jones all walked out to left field and persuaded the fans to stop throwing debris.
Split into simpler sentences: National League president Chub Feeney spoke to Mets' management and threatened the Mets with a forfeit. That prompted Mets manager Yogi Berra, as well as Willie Mays, Seaver, Staub and Cleon Jones to walk out to left field to persuaded fans to stop throwing debris.