Rangers have confirmed the signing of Doncaster winger Harry Forrester from Doncaster Rovers.
The 24-year-old, who has worked with Warburton before at both Watford and Brentford, has signed on an initial six month contract.
Forrester, who turns 25 on Saturday, came through the youth ranks at Watford and Aston Villa, and while he made no senior appearances for either, he gained some experience of what to expect in Scottish football with a loan spell at Kilmarnock in season 2010-11.
From Villa, Forrester spent time on trial with Ajax before joining Brentford in the summer of 2011 on a two-year deal, where he went on to make 69 appearances in all competitions and scored 11 goals in the process with the most significant of those being a late penalty against Chelsea to earn the Bees an FA Cup fourth round replay in January 2013.
The deal will become official when the transfer window opens on Saturday, although it is unlikely international clearance will have been received by then, thus meaning Forrester will have to wait until the Scottish Cup tie with Cowdenbeath on January 10 for a chance to make his debut.