The highly-rated winger has committed himself to the club until 2015 despite reported interest from the likes of Chelsea and Manchester City.
Goalkeeper Jonathan Flatt joined the 18-year-old in agreeing a new contract of the same length.
Wanderers chief executive Jez Moxey told the club's official website: "We are talking to several of our younger players at the current time and are delighted to have reached agreement with Zeli and Jonathan.
"It is the next stage along each of their respective developments, but it is just the next stage and they both know they need - and indeed want - to continue improving.
"Zeli has been a regular in the new Under-21 team which has performed well this season, and also made a brief senior debut as a substitute in the Capital One Cup tie at Chelsea in September.
"With his future now secured he can concentrate on continuing his progress within the Development Squad and aiming to fulfil his potential."