Clough is keen to add to his attcking options at Bramall Lane having terminated the contract of much-travelled Marlon King and allowed Lyle Taylor to join Partick Thistle on loan until the end of the season.
"We have made enquiries. Many of the enquiries we've made want to get the weekend and the FA Cup games out of the way first," said Blades boss Clough, "We have a long list of names and Conor Sammon is on that list. But the list is about 15 names long. In fact, any striker in the Championship that isn't currently in the starting XI - and who interests us - we will be making an enquiry."
He has also expressed an interest in fellow Rams forward Johnny Russell with this deal looking dead for the time being.