The 30 year old Egyptian goalkeeper had arrived at Bramall Lane for three days on trail but things didn't work out and will not now be signing for the Blades.
Warnock told BBC Radio Sheffield: "Rami came up for three days and we liked what we saw.
"We asked him to keep in touch and if something came up we'd look at doing something but I'm not on the look out for a new keeper at the moment."
Signed from Swedish club Djurgaardens in September 2002 Shaaban would only make 3 appearances during his stay at Arsenal, he did however, in January 2004 join West Ham on loan but failed to make an appearance before leaving Highbury for Brighton in February 2005 where he mastered 6 games for Withdean club.
Had Shaaban signed he would have became the first Egyptian to have ever played for United.