Hello,
if I play "Call for Reserves":

Action: Return target unit you control to its owner’s hand. Then, put into play from your hand a unit with printed cost 3 or lower.

Can I play the unit on a quest?

From the rulebook:
To send a unit on a quest, a player plays the unit on top of the quest card when he plays that unit from his hand.

I know that there is a difference between "playing" and "put into play" (via card effect) but I would like a confirmation to the fact that this difference not allow me to play the unit on a quest, because the card is in both cases played from the hand.

Horatius said:

No it isn't, in the second case it is put into play from your hand You can only play cards on the quests (wating in ambush allows it), but not with put into play effects.

Ok, thanks for the prompt reply.