Andrew Jackson Leonard's 1871 Washington Olympic baseball contract is among the most intriguing lots for sale in Heritage Auctions' upcoming sports sale.

Andrew Leonard's 1871 baseball contract is one of the oldest on the market

The document is among the oldest surviving baseball contracts and is expected to sell for in excess of $20,000.

Leonard was one of baseball's earliest heroes. He played for several teams in the major leagues between 1871 and 1880, when his vision began to fail and he was forced into retirement.

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