The League One club confirmed on Tuesday that the striker would be allowed to train with them, at the request of the Professional Footballers' Association (PFA).
Evans was released from prison last month after serving half of his five-year sentence for rape, with the Welshman having left Bramall Lane when he was convicted of the offence in April 2012.
His potential return to United in a full-time capacity - a matter the club are "not prepared at this time" to make a call on - has been met with strong criticism in some quarters, but manager Clough has no qualms about Evans training with his side.
"I think everything has been deliberated properly, nobody has rushed into any decisions at the club," the former Derby County boss told Sky Sports News.
"Everybody realises the gravity of the situation and seriousness of everything and that's why it has taken so long to even get to this stage.
"It has been prompted by the PFA and that's as far as it goes now.
"We deliberated as a club for some weeks and came to this decision. According to the law of the land he is entitled an opportunity to resume his career."
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