De Gea's focus was hampered during Spain's last appearance at a major worldwide tournament when his name became linked with a sexual assault case in the build-up to Euro 2016.
The goalkeeper strenuously denied the accusations at the time, with no evidence found to press charges - but Sanchez expressed misgivings and said he "didn't feel comfortable" with De Gea representing Spain at the tournament.
But the 27-year-old gave little away when asked about his future at La Furia Roja's training camp for the tournament in Russian Federation. "The issue is that what he said back in the day was in public and that is why I think the apology should also be a public one".
"I am a very calm guy and it is hard for me to be affected, but you have family, people close to you, who are affected more".
Sometimes it's nearly as though we have a selective memory and tend to focus, not on Spain's performances in the last two tournaments but in three previous ones which we won.
Spain take on European champions Portugal in their Group B opener on June 15.
David De Gea says discussions about his future at Manchester United are not important as he focuses on the upcoming World Cup. We have a great national team but every game is a battle for us. "We will try to do our best". "But Portugal is not only Cristiano, they have a great national team, they won Euro 2016. I still don't know what was behind it all and everything that came out a few days before the start of Euro 2016".
"They haven't been fair to me".
I'm a quiet, peaceful guy and I'm not usually affected by things - personally, I wasn't too affected by it but I have family, people who are close to me and it's not right that they should be affected.
"Football is football and a thousand things can happen.", he added. It's all water under the bridge now.
"It's also true that the majority of public people have disrespected me and haven't bothered to apologise to me in private. It is important to be focused and to play at 100 per cent". "It is easy to talk about others in this country".