Add the cream cheese, cheddar cheese, onion, horseradish, Worcestershire sauce and red pepper flakes to a food processor. Blend until combined but still has a bit of texture. Taste for seasoning and add salt and pepper if needed.
Place 2 Tbsp of cheese mixture in a resealable bag and set aside.
Form remaining cheese into the shape of a football on a serving plate. Press the pecan pieces into the sides of the cheese, completely covering the cheese. Cut a small hole in the corner of the resealable bag containing the 2 Tbsp of cheese. Pipe "laces" onto the top of the "football."
Serve with crackers or pita chips. Play ball!
One Last Thing
Prepared horseradish is different from horseradish sauce. If you use the sauce instead, your cheese ball will be softer and have less kick.