Jersey fly-half Aaron Penberthy is expected to be out for two months after breaking his leg.
Penberthy came on as a first-half replacement for winger Ed Dawson in the 29-13 loss at Leeds but was helped off the pitch after the incident.
The 21-year-old took the ball into contact but fell awkwardly and suffered a fractured fibula.
Jersey, who are 11th in the table, hope Penberthy will be ready to return by early February.
Penberthy, who joined the club from Cornish Pirates in April, said he was expecting a lengthy lay-off.
"Thank you everyone for the messages. Verdict is a broken leg. Hopefully be back out there again before the end of the season," he tweeted.