One way you could do this would be to use a code replacement file with a 2 digit code for each player name. Add this text file in the Set Code Replacements dialog from the Edit menu -> Settings option.
Select one image on the Contact Sheet and then hit the Spacebar to open the Preview window. The Keywords panel from the Image menu will let you append your 2 digit code as a new keyword. Make sure the bottom menu is set to the When applying, append keywords option. Enter the player code in the bottom field. Use the Apply to selected photos button at the bottom or the Command-Shift-a shortcut, to save the player tag. Advance to the next Preview and repeat.
To see the player names on the Contact Sheet, add the code replacement variable ={keyw:-2}= to one of the label fields. Go to the Contact Sheet preference page to enable a new label for the code replacement variable. I hope this helps as an alternate solution for your tagging requirements.
Best regards,
--Bob
