Chelsea manager Maurizio Sarri said he is "very confident" that Willian will stay with the club this summer but admitted the future of Thibaut Courtois depends largely on the goalkeeper's decision.
Willian returned to preseason training with Chelsea late after problems returning from Brazil.
The forward has been linked with a move to Manchester United and Barcelona, but Sarri said he was not concerned that his delayed arrival had anything to do with engineering a move away.
"I spoke to him yesterday about [being late]," Sarri told a news conference ahead of Sunday's Community Shield game against Manchester City. "It was a very positive conversation and I am very happy about it. There is not a Willian problem."
Asked if he expects the 29-year-old to be part of his midfield this season, Sarri said: "Yes I do. Very confident."
Sarri was less sure about the future of Courtois amid speculation that the goalkeeper wants to leave Chelsea and join Real Madrid.
"At the moment Courtois is the goalkeeper of Chelsea," Sarri said. "I don't know in the future. It depends on the club, it depends especially on him, but I hope Courtois will be our goalkeeper."
The Wembley clash with last season's runaway Premier League winners will give Sarri a taste of what to expect over the next nine months. It will also be his first experience of England's iconic stadium.
"I am looking forward to playing in Wembley, it is my first time. The match will be very difficult for us," he said. "I want to win, because it is very important to have a trophy immediately. At this point of the season it is important the performance, we have to improve up close."
Sarri conceded the game is probably a bit early for his squad, many of whom are not yet up to match speed.
"Of course the players have not got the top level now, a lot of trainings and travels and matches," the Italian said. "We are not at the top level now but we have to try to have a good performance and result."
Information from Reuters was used in this report.