The 31-year-old's initial month-long stay at Bramall Lane ended after Saturday's 1-0 defeat to Barnsley, but Palace boss Neil Warnock has allowed an extension until the end of the year.However, he will not return until after this weekend's FA Cup first-round clash at Crewe as Palace do not want him cup-tied.
"We are hoping to get Paddy back, it will be after Saturday because Palace don't want him to play in the FA Cup," Clough said in his pre-match press conference on Wednesday.
"He has been a brilliant influence, it's not done yet, but it's agreed in principal.
"We are very grateful to Neil again for his help in it and hopefully he will get some more games in the next six weeks or so.
"We look a bit more solid when he's around and he has formed a good partnership with Jay McEveley.
"We haven't gone beyond January, the travelling is a bit of an issue with his family living in south London, but if we can secure him until the end of December we will be delighted with that."
Meanwhile, Clough's move for out-of-favour Blackpool striker Steven Davies has been put on hold following Lee Clark's arrival at the Seasiders.
Clough, who worked with the 26-year-old at Derby, had hoped to sign Davies to bolster the Blades' attacking options, but the deal has been delayed.
"It's not about money, a new manager has gone in at Blackpool so it's more about that than anything else," Clough added.
"He is one of the targets, he gets goals, he's a good all-round player and at this level he will score goals, especially with the amount of chances we are creating."