Personalized Baseball Irish Shamrock Youth T-Shirt. A green baseball with the imprint of a shamrock is a unique Irish themed gift design for baseball players and fans on birthdays and St. Patrick's Day. Let the good times roll in a durable T-Shirt that takes kids from school to play in an amazing array of colors. 5.0 oz., pre-shrunk 100% cotton. Seamless 1x1 rib collar.