KUALA LUMPUR, June 16 -- World Cup fans have spotted a new detail on players' shirts this year: small sleeve patches that are set to feature in future Topps trading cards, though little has been officially explained about them.

Topps, an American company best known for sports trading cards and sticker albums, is owned by global sports merchandise giant Fanatics.

The patches, which mark milestones such as debuts and past awards, have appeared with minimal acknowledgement from Fifa, The Athletic reported.

"This deal starts only in a few years and will run for several years and various tournaments, but it also includes the first-ever players jersey patch program that will actually kick off at this upcoming Fifa World Cup," Fifa president ...