The Spain captain pledged his commitment to Atletico just days ago, but now admits his future could be out of his hands.
Morata said from Spain's Euros camp: "What I wrote is what I think from the bottom of my heart, but many times I say that for me there are difficult moments in Spain, sometimes it's complicated.
"What I wanted was to stay calm. In the end it's all a matter of sensations and the people close to me know this, but in football nothing is certain and we will have to see how things go. Now I just want all this to continue in the best possible way and for me to have fun because it could be my last European Championship with the national team.
"I'm thinking about retiring from the Spanish national team. We'll see how things go. It's difficult to make a decision like that, but it's a possibility."