The 25 year old winger was linked with the Blades through numerous newspapers.
He has now re-joined the London outfit on a season-long loan. The recent signing of David Cotterill and the pursuit to sign Lee Martin has now signalled that if Cook was actually a target he may now not be needed.
Cook said: "Once it was clear I could leave Fulham there was only one club I wanted to move to."
Cook had a spell with Rangers from 2004-2007 and after his places at Craven Cottage are limited he has joined fellow London rivals QPR. He has made zero appearances for Fulham and has now been on loan four times on his career.
Meanwhile another rumoured United target was Andrew Driver. He has recently extended his contract with Hearts.