Oxford United signed Chelsea goalkeeper Jamie Cumming on a permanent deal.
The 24-year-old played 23 times for the U's while on loan during the second half of last season, helping the club win the League One play-offs.
Oxford have not disclosed whether they have paid a fee for the former England youth international, who was still under contract at Chelsea, or the length of his deal.
“Jamie showed real improvement over his loan spell last season, and he was a very important figure in our successful play-off campaign," head coach Des Buckingham told the club website.