Hines Ward -- You MIGHT Be the Father!

Former NFL star Hines Ward ... come on dooooooown ... it's time to play ARE YOU THE FATHER???

A woman named Melanie Smith filed a lawsuit in Georgia this month ... claiming the former Pittsburgh Steeler is the biological father of her 1-year-old daughter.

According to docs, Melanie wants Hines to admit he fathered the kid -- and if he refuses, she wants a judge to order a blood test in order to establish paternity.

The maybe baby mama is also asking Hines to start coughing up child support ... if it's determined the child is actually his.

A judge has yet to rule.