The United boss has a doubt over first-choice Neil Sullivan ahead of tomorrow's clash with Norwich City, but Warner will provide Blackwell with a suitable replacement if Sullivan fails to recover from a dead leg.
Warner turned professional with Liverpool in 1994, but never made a first team appearance for the Reds. During his time at Anfield, he had loan spells at Swindon, Celtic and Aberdeen making 11 appearances in total.
In 1999 he moved to Millwall, and was an ever present for two and a half seasons before losing his place through injury in January 2004, which ultimately cost him a place in the FA Cup Final against Manchester United that year. He made 224 appearances for Millwall.
He joined Cardiff City in July 2004, making 30 appearances for the Bluebirds in 2004-05. However, he was signed on loan by Fulham, with the Cottagers going through a goalkeeper crisis at the time, similar to Leeds now, following the sale of Edwin Van Der Sar, and injuries to Mark Crossley and Jaroslav Drobny, and Warner was immediately thrust in to Premiership action.
However, despite making the move permanent in January 2006, he soon found himself back on the bench when Antti Niemi arrived at the club soon after.