Chelsea manager Antonio Conte expressed surprise on Friday over Eden Hazard's call-up by Belgium.
Hazard, 26, has not yet played for Chelsea this season after fracturing his right ankle on international duty in June.
But he has been called up by Belgium coach Roberto Martinez for next month's World Cup qualifying matches against Gibraltar and Greece.
"I only knew 20 minutes ago and for sure I'm a bit surprised by this decision," Conte said.
"I was a coach of the national team with Italy, so I respect the decision of the coach. If Hazard isn't ready, he will not play. It's why he doesn't play with us."
Hazard was scheduled to play for Chelsea's under-23 side on Friday as he nears a return to first-team action, but he is not expected to feature in Sunday's home game with Everton.
"I see him every day," Conte told reporters at Chelsea's Cobham training base southwest of London.
"In this situation it's very important to give the right time to players to recover. Also he is a very important player for us.
"If someone thinks to accelerate the process, it is not the right way. It's a big mistake. In this moment we must pay great attention and not make any mistakes."
Gary Cahill will miss the meeting with Everton through suspension following his opening-day dismissal against Burnley, but Cesc Fabregas returns after serving a one-game ban.
Conte has been frustrated by Chelsea's failure to significantly strengthen his title-winning squad, but he said it would not be a problem if they make no further signings before next week's transfer deadline.
"For sure, the club is trying to strengthen our squad, our team. They are working very hard to do this," said the Italian, whose side won 2-1 at Tottenham Hotspur last weekend.
"We have to continue to work. Also if we continue to stay with these players, I am very happy.
"My focus is only on the pitch, then there is the club. The club is working hard and we will see what happens at the end of the transfer market."
Meanwhile, the Football Association revealed on Friday that Chelsea wing-back Kenedy has been given a warning regarding social media posts he published during Chelsea's pre-season tour of China.
The Brazilian was sent home by Chelsea after posting two videos on Instagram, one containing a profanity and one showing a sleeping security guard along with the caption: "Wake up China. You idiot."
He subsequently apologised.