Cambridge have signed teenage keeper Jamie Waite on non-contract terms.
Waite, 19, joins the Conference club after impressing during a trial spell at the Abbey Stadium during pre-season.
The former Rotherham United youngster and Thailand international provides further cover for on-loan West Ham keeper Darren Behcet and Scott Howie.
U's boss Rob Newman told the club website: "Jamie enhances our goalkeeper situation. It's good for us to have three confident keepers on the book."