The baseball you have could be a Cincinnati Reds baseball from 1990 or 1991 the only two years the three players mentioned appear on the same team. A 1990 Cincinnati Reds Team Signed Baseball with the key signatures: Davis, Larkin, and Piniella is worth about $250.-$350. A 1991 baseball with the same key signatures is worth about $75.-$100. Value is based on average prices of recently closed auctions. Prices may vary based on condition, and the type of authenticity that accompanies the baseball. Prices may also vary based on the amount of signatures, and key signatures acquired. The more complete the baseball with key signatures the more valuable. I will leave a link for Cincinnati Reds team signed baseballs complete with lists of key signatures, and links to full team rosters. If you can't narrow it down to one particular year, and it is signed by various players from different years the baseball would be a Cincinnati Reds Multi signed baseball and could be worth less. Keep in mind that a signed baseball without a creditable letter of authenticity could sell for half the market value or less.