Porter & York’s 28 day aged, Prime Grade top sirloin steak is very lean with a rich beef flavor. This steak is also commonly referred to as a baseball cut or center cut sirloin. Porter & York’s Prime Grade beef steaks and roasts are fresh, and never frozen, from cattle raised on family farms in Nebraska. Only the top 2% of all beef is graded as Prime. With abundant and rich marbling content, these cuts are found only in the finest dining and grocery establishments.