Cadamarteri has a throat infection so is laid up at home, while Webster has a minor groin problem and will not be risked on the plastic pitch.
Skipper Lee Wilkie and fellow long-term injuries Jon Daly and Kevin Smith are also out.
Cadamarteri's absence will give either Damian Casalinuovo, Andis Shala or Johnny Russell the chance to partner David Goodwillie.
Steve Banks will make his competitive debut in goal in place of Nicky Weaver.
United (from): Banks, Dillon, Dods, Kenneth, Dixon, Kovacevic, Gomis, Buaben, Conway, McCord, S Robertson, D Robertson, Myrie-Williams, Russell, Shala, Goodwillie, Casalinuovo, Weaver.