Terry left England boss Roy Hodgson with a major headache on Sunday night when he announced his retirement from international football.
Caulker, who had a successful year on loan at Swansea last season, is yet to make a Barclays Premier League start for Spurs, but the 20 year old was still called up for England's friendly against Italy in August.
"It's definitely possible," Freund said when asked if Caulker could replace Terry for England.
"He is similar (to Terry). He has already been called up for the national side and he's definitely one of best centre halves in England.
"He is like a rock in the defence, he's very tall and strong, and is difficult to beat in a one-on-one situation. He's very talented and wants to improve every game.