Goalkeeper Alex Cisak has returned to his parent club Leicester City following the conclusion of his month-long loan spell at Oxford United.
Cisak did not make a first-team appearance in his time with the U's.
Meanwhile, QPR have given the U's permission for on-loan midfielder Stefan Bailey to become cup-tied in their FA Cup qualifying tie next week.
But boss Jim Smith is waiting to hear whether Ipswich will allow them to field on-loan striker Jordan Rhodes.
Oxford will visit Merthyr Tydfil in the fourth qualifying round, with the winners earning a place in the first round proper.