Louis van Gaal would be interested in signing Cristiano Ronaldo, but does not think Real Madrid will sell him.
Chelsea boss Jose Mourinho has played down speculation about signing Cristiano Ronaldo.
Curtis Davies and Nathan Redmond have already attracted top-flight attention, while the likes of Marlon King, Darren Ambrose, Hayden Mullins and Peter Lovenkrands are also tipped to be offloaded before the transfer window closes.
Although no offers have been confirmed, Premier League new boys Hull City are reported to be chasing Davies' signature and Clark admitted there has been interest in a number of his players.
"There have been a few enquiries about them," he told the Birmingham Mail.
"We have said to the four lads about the free transfers and there have been one or two calls.
"There's not yet been anything concrete. We're still waiting on that.
"They're experienced, top-quality players though, so I presume there will be interest in them."