England defender Cahill has been Chelsea's on-field skipper for much of this season, with Terry out of favour.
Terry, now 36, has played in the Chelsea first team for more than 18 years and is out of contract this summer, with many anticipating his exit.
Terry has not made a Premier League start since September, initially due to injury, and his only starts have come in the cup competitions.
Cahill, though, is adamant he is not out to replace his fellow central defender.
He told the London Evening Standard: "I would never try to fill John Terry's boots
You can never fill that position.
"When I took over as captain this season, either through him not being picked or not being available, it was a privilege to do that.
"Firstly, I have learned from how he manages himself, how he plays and how he does things
But secondly, I never thought for one minute, or will ever think, that I'm replacing him.
"He is right at the top and whoever comes in after him is never going to achieve what he's done at the club.
"Nothing has changed in my game since I had that armband, apart from the fact I'm now 31 and I have learned a lot from someone like him
I will continue to learn from him while he is at the club."
The Blues hold a 10-point lead at the Premier League summit with 10 games to go and are into the FA Cup semi-finals, where they face Tottenham.
Chelsea head coach Antonio Conte has long insisted Terry's future will be determined at the end of the season.
Source : PA
Source: PA