Harewood failed to start a single Premier League game last season and he is ready to move on in search of regular first-team action.
Hull and Middlesbrough's interest in the 29-year-old was already out in the open but the player's representative, Phil Sproson, says the there are a host of other clubs chasing the forward.
"I think it is most likely Marlon will move on this summer," Sproson told Sky Sports' website.
"He is keen to be playing regular first-team football and he accepts the situation at Villa.
"There are a number of clubs interested in Marlon, including Hull and Middlesbrough, but nothing has been decided yet.
"It depends on whether any interested club can agree a deal with Aston Villa before anything can happen."