Known by his nickname, The Wizard, the Chelsea player is back in the national team one year after leaving international football because of a long-standing feud with the previous coach.
Ziyech looked relaxed in training on Tuesday as he prepared to play his first competitive match since returning to the squad.
Last week he scored an incredible goal from inside his own half as Morocco beat Georgia 3-0 in their final warm-up friendly.
The Atlas Lions will meet European heavyweights, Belgium, just four days after their Croatia match. Their final Group F clash will be against Canada on 1 December.