Willian says he does not know why Chelsea allowed Ruben Loftus-Cheek to go on loan to Crystal Palace after facing the 21-year-old in Brazil's goalless draw with England on Tuesday.
Loftus-Cheek was forced off the pitch after just 35 minutes with a back injury at Wembley, days after being named Man of the Match on his senior England debut for an impressive performance in central midfield against world champions Germany.
And speaking after Tuesday's match, Willian, who came off the bench against Gareth Southgate's England side, said he was at a loss to explain Chelsea's decision to send Loftus-Cheek to Palace for the season, where he has featured in seven of 11 Premier League matches.
"I don't know why he is at Crystal Palace now," Willian told reporters, before adding with a smile: "He has to come back!"
Chelsea have struggled for quality options in central midfield at times due to injuries, with deadline-day signing Danny Drinkwater still working his way back from a calf problem, Tiemoue Bakayoko managing knee pain and N'Golo Kante only recently recovered from a hamstring injury.
Willian said that Loftus-Cheek is "a very good player" and added: "He is strong, he has quality. He has a great future."
Brazil spent much of Tuesday's friendly on the front foot but could not find a way through the impressive defence of a youthful England side, with Liverpool's 20-year-old Joe Gomez named Man of the Match for his part in stifling Paris Saint-Germain star Neymar.
"England are a very strong team with young players, quality players," Willian added. "It was difficult for us to find spaces because they had a lot of players behind the ball. It was a good game and we created four or five chances to score but we didn't.
"England always have good and strong players. They can improve a lot, like us. I think they can do that."