There is a list of these on the [English Wikipedia][1]. Here's the ones I remember having seen in Fifa 14. They are always color-coded to show which area of the game they belong to. For the center positions the left and right seems to refer to the current formation. I.e. a player cannot be a `LCB`. He's a `CB` on his bio, but he is playing the `LCB` position.

Goalkeeper: Orange

- `GK`: Goalkeeper

Defense: Yellow

- `CB`: Center-back
- `LCB`: Left center-back
- `RCB`: Right center-back
- `LB`: Left-back (Full-back)
- `RB`: Right-back (Full-back)

Midfield: Green

- `CM` : Centre midfield
- `LDM`: Left center midfield
- `LAM`: Left attacking midfield
- `RDM`: Right center midfield
- `RAM`: Right attacking midfield
- `CDM`: Centre defensive midfield
- `CAM`: Centre attacking midfield
- `LM` : Left midfield
- `RM` : Right midfield

Attack: Blue

- `ST`: Striker
- `CF`: Center forward
- `LW`: Left winger
- `RW`: Right winger
    


  [1]: http://en.wikipedia.org/wiki/Association_football_positions