Some of the sets Upper Deck puts "Lettermen" sets together with patches that spell out things that are not the players name, like their team. Most of those are "player worn" not "game worn" or just "memorabilia."
Player worn means that it was put on and taken off for the express reason to be cut up and put into cards.
For example, this Ramik Wilson card has the following letters for sale on COMC: U, D, O, and G. All of those are in the team name "BULLDOGS" and he played for the University of Georgia.
https://www.comc.com/Cards/Football/...ilson/10201072
On the back it says it is a "Manufactured Patch" which means it was not even worn; the COA on the back is only certifying the autograph as authentic. Post a picture of the card you're talking about, but it's probably similar to this.