Cahill, 31, has led Chelsea for the majority of the campaign with Terry, who is leaving the club at the end of the season, starting only five league games.
"Gary is our vice-captain this season. He put the armband on every time John didn't play," Conte said before his team host relegated Sunderland on Sunday.
"For sure, Gary has good prospects of being captain, but now it's important to finish the season.
"To start to think about next season is very dangerous because we have different targets still to reach."
Conte is yet to make a decision on whether Terry will start in what will be his final game at Stamford Bridge but is certain the 36-year-old has the qualities to succeed elsewhere.
"John has all the possibilities to continue his career," he added.
"We all know he prefers to play regularly and for this reason he decided to leave.
"It is very important to feel yourself, to feel your body, your mind, to see if you have the desire to fight to arrive every day..and John has all of these characteristics."
The Italian refused to dwell on signing a new contract at the club, saying Chelsea are focused on securing personal and collective milestones up for grabs in the final two games of the season.
"We reached an important target, to win the league, and now on Sunday we have two targets. To try to win the 30 games in this league and then to help the goalkeeper (Thibaut Courtois) to win the golden glove," said Conte.
"Then we have the FA Cup (final) against Arsenal. Every single player, the coaches and the manager, we have the time to discuss with our club."