This rare pre-rookie contract is signed by Hall of Famer Phil Niekro for his 1963–64 winter season with Mayaguez in the Puerto Rican League, predating his legendary 24-year Major League career. The four-page, Spanish-language document details his $700 monthly salary and expenses, and bears a strong “Phillip Niekro” signature in blue ballpoint on page two. The contract shows expected age wear, including light darkening, small stains, filing holes, and a minor fold-line tear, but remains an exceptional early-career artifact from baseball’s greatest knuckleballer.