Unless it is of very poor quality, a player can never add any physical damage to the CD. Scratches could come because of may reasons:
1. Physical handling. For example, if the CD does not site well inside the jewel case, every time you move the case, the CD will rattly inside and get scratched.
2. Dirt in the player's tray. If there is a lot of dust in the player's tray, they could add to tiny scratches when the CD is played.
3. Carelessness. When we handle CDs, I have seen many people not holding the CD properly. You should never touch the CD surface. Always held it by the edges. In addition, never place the CD by itself on a table or somewhere. When not inside the player, it should only be inside the jewel case.
4. I have seen a number of CD jackets (that hold 50 or 100 CDs) as being the cause for scratches. Every time you remove or insert a CD, you have to use a bit of force. This could add scratches to the CD.
Cheers