The French midfielder, along with an unnamed Greek trialist, had spent a week training with the Tykes.
But Hill told the Sheffield Star: "We were poles apart unfortunately when it came to signing Malaury. He's gone back to France, but I was reasonably happy with him.
"I'd have liked to have kept him because he's got good pedigree, but there was a certain element of risk - and that risk was too big in the end.
"The Greek player came highly recommended but he needed a lot of work doing with him and, although we need players for the future, was also need players for the hear and now.
"I've got four trialists in this week so it will be good to have a look at them."