Don Mattingly signed sports memorabilia is a top-seller. This Don Mattingly Autographed New York Yankees Jersey - JSA Certified Authentic has been certified by JSA and will come with a Certificate of Authenticity (COA). Don Mattingly autograph memorabilia collectors will love this quality signed product. This item is in stock and ships out same day. Autographed New York Yankees memorabilia is valuable and a perfect gift idea for a diehard fan.