Bristol City head coach Lee Johnson says keeper Frank Fielding will miss the start of next season after having surgery on an ankle ligament injury.
The 28-year-old picked up the problem in an under-21 game last month and is unlikely to return until September.
Team-mates Korey Smith and Aden Flint have also had "clean-up operations" on ankle and knee injuries respectively and should be back for pre-season.
"Frankie is going to be a while in rehabilitation," Johnson said.
"We've got a great physio team who will work with him and try and improve that timescale as best as possible.
"Ideally you want three goalkeepers for training purposes, so even then you'd need to add another."
Fielding's injury leaves Bristol City with only youngsters Max O'Leary and Jojo Wollacott as cover for first-choice goalie Richard O'Donnell.