Aston Villa striker Darren Bent is set to make a loan move to Brighton in the next 48 hours, according to Sky sources.
Juan Cala wants to find 'another club ASAP' and believes Cardiff have acted without respect towards him.
The 21-year-old, who played in a 5-1 Capital One Cup defeat at St Andrew's in August, impressed City staff during a recent trial period with the club.
Manager Lee Clark told the club website: "We have been scouting Olly for a while now and he was one of Barnet's standout performers during our tie earlier this season.
"Olly has impressed us further during a recent trial period and we now look forward to seeing how his development continues over the coming months."
Lee, son of former England international Rob Lee, began his career as a West Ham trainee before signing for Barnet last summer.