Cahill confirmed as Chelsea captain
Sarri had been non-committal about the identity of his captain for the current season, with Eden Hazard and Cesar Azpilicueta both given the responsibility.
The Italian has opted to leave Cahill – who took over the responsibility from John Terry – as club captain, with Azpilicueta his deputy.
Azpilicueta is likely to wear the armband more given Cahill's back-up role this term, but Sarri insists the former England defender remains his leader.
"As we have seen in the last matches, the captain is Cahill, like in the last match [against Derby County]," Sarri told a media conference.
"When he isn't on the pitch our captain is Azpilicueta.
"Cahill was the captain last season. I spoke with his team-mates and they all told me he really was a very good captain."
Sarri says as could been seen in the last game, Gary Cahill is the Chelsea captain and when Cahill is not on the pitch, it is Cesar Azpilicueta. #CHECRY— Chelsea FC (@ChelseaFC) November 2, 2018
Despite the vote of confidence from Sarri, Cahill's future at Stamford Bridge remains unclear.
"It depends on him," the former Napoli boss added when asked if Cahill could leave in January.
"He played very often in the last seven or eight matches. I don't know [if he'll leave]. It depends on him and the club.
"For me Cahill is very important on the pitch and out of the pitch."