Harewood, who is out of favour at Villa, impressed during a recent loan spell at Championship side Newcastle, bagging six goals in 15 games to provide a timely reminder of his scoring ability.
And now Brown and Zola are considering a move, with a loan or permanent switch on the cards for the side that can put a deal on the table.
Hull came close to signing Harewood in the summer but the transfer fell through on deadline day, although the Tigers could still be in line to bring the striker to the KC Stadium.
Sproson told the Hull Daily Mail: "I have spoken to both Phil and Gianfranco and both said they were interested in Marlon if they can get the deals sorted at their clubs.
"Phil said he is still interested in Marlon and that he has watched him a couple of times recently.
"He said that he had been impressed that Marlon has clearly got the bit between his teeth again, but he said he had to get two or three players out before he could bring anyone in.
"That is where we left it, and it is a similar situation with West Ham."
The Hammers are short of money at the moment, while Hull chairman Adam Pearson has vowed to cut the KC Stadium wage bill - culling squad players in the process.
Villa are eager to recoup some of the £4million fee they forked out in 2007 following Harewood's move from West Ham as the 30-year-old could leave for free at the end of the season when his contract expires.
Sproson explained that the money issues at the two clubs meant no negotiations had begun.
He added: "Both clubs have registered their interest, but because of their situations, they have not taken it further as of yet.
"Our message has been that if they want Marlon, he is here and waiting and his record shows that he scores goals.
"He scored six goals in 15 at Newcastle and that was without a pre-season.
"He can do a good job for a Premier League team and we hope he will be playing that level come the end of the window."
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