Left-back Ryan Dickson has turned down a new contract with the U's to join League One rivals Crawley Town.
He and fellow out-of-contract players Mark Cousins, Dom Vose and David Wright were offered new deals last month, but Dickson has opted to sign a two-year deal with the West Sussex team instead.
The 27-year-old spent just one year at United Way, signing last summer after a trial. He made 35 appearances (30 starts/5 subs).