
Oxford have made Jonathan Meades their first signing of the summer, while Scott Davies and Deane Smalley have signed new deals at the club.
Chris Wilder has urged Oxford supporters to be patient for new signings following a slow start to the summer.
Portsmouth have signed striker Tom Craddock on a two-year deal from Oxford United.
Oxford have released 12 members of their first-team squad, including joint top goalscorer Tom Craddock and defender Michael Duberry.
Tyrone Marsh and Max Crocombe will remain at Oxford for at least another 12 months after the club extended their contracts.