Ipswich have been forced to register 40-year-old coach Andy Rhodes to solve a goalkeeping crisis.
He is likely be on the bench at Watford after 17-year-old Shane Supple suffered a suspected broken toe in action for the reserves on Wednesday.
Lewis Price will continue to deputise for first choice Kelvin Davis, who is still ruled out by a back problem.
Rhodes, who took up his post in the summer, has not played a senior game in almost six years.
Royle said: "Going without a keeper on the bench is one
possibility, but we have also decided to register Andy.