Cardiff will allow long-serving Kevin McNaughton to leave this summer along with Danny Gabbidon and Nicky Maynard.
Highly-rated Atletico Madrid midfielder Saul Niguez has signed a new five-year contract.
And his time at Oakwell is about to come to an end, with the final touches being put on his exit.
"He's an exceptional person, he's played at the top level in most leagues in Europe," Hill said.
"At 29, he slipped down the levels and I thought we could pursue a possibility of resurrecting him, but that hasn't worked out.
"But he retains the ability and pedigree, but his vision is not the same as the manager's.
"It is amicable, but the plan to resurrect him hasn't worked.
"We will be pursuing a different direction to Mido."