Playing with Finest Ketel Marte in CF and his card says he is a good fielder but the icon is silver when a ball is hit to him - glitch?
The shield underneath the fielder only represents 1 attribute which is fielding. The shield on the player card is an accumulation of all fielding stats, including reaction and I think also arm strength/accuracy. Not sure about the arm, but I'm sure about the fielding + reaction. So if a guy has 79 fielding and 99 reaction, chances are his shield on the player card is gold or maybe even diamond, but the shield during gameplay is only a silver because it only represents that fielding attribute without the reaction attribute.
Ketel Marte has 79 fielding and that's why his shield during the game is silver.