Cahill captained Chelsea to their FA Cup win last season, his sevenmth trophy at the club
Chelsea assistant manager Gianfranco Zola says it is "understandable" Gary Cahill is "upset" about a lack of game-time at the club this season.
The defender, whose contract expires at the end of the season, had not featured this campaign before playing 21 minutes off the bench at West Ham on Sunday.
He was captain last season and has said he will ask to leave the Blues in January if he continues to be left out.
But Zola said Cahill, 33, has behaved like a "top professional".
"It is totally understandable Gary is upset and we want him to be upset. It means he cares," former Chelsea striker Zola said.
"He has been a top professional; he is doing everything correctly."
Cahill, who stepped aside from England duty in August, joined Chelsea from Bolton in January 2012.
He has won every major club honour with the Blues, including the 2012 Champions League, and was captain for their 2016-17 Premier League-winning campaign and May's FA Cup success.
He missed the start of pre-season after being part of England's World Cup squad and was not in the Chelsea squad for the first five Premier League matches of the season under new boss Maurizio Sarri.
Zola suggested Cahill could feature in the Blues' Carabao Cup third-round tie against Liverpool on Tuesday.
"He needs to be patient because he came late, and the players that were already here did very well," Zola said.
"He will have his chances, then it's down to him to take those chances in the best way."
Source: bbc.com