Harry Worley has joined Oxford on a three-year deal following his departure from Leicester.
The 21-year-old defender was part of Chelsea's squad between 2005 and 2008 but a lack of first-team action saw him loaned out before making the move to Leicester.
Last year he spent the season on loan at Crewe, playing 22 times, and is now delighted to be embarking on a new challenge at the Kassam Stadium.
Worley told the club's official website: "I'm really excited to have signed for Oxford United.
"I followed the club a bit last season and I know there's a real buzz going on around the place so I'm happy to be a part of that.
"I know that I'll face a tough battle to get into the side but I'm prepared for that and look forward to showing people what I can do."
Oxford manager Chris Wilder shares Worley's enthusiasm, saying: "We're pleased to have signed Harry on a contract for the next three years.
"He's got a good CV and a fantastic pedigree that we feel will stand him in good stead."