Harewood's contract expires at Villa Park this summer and he will not signing a new deal as he looks for a new challenge.
The 30-year-old has endured a frustrating last couple of seasons at Villa, failing to hold down a regular place in Martin O'Neill's starting XI.
Harewood enjoyed a successful loan spell at Newcastle last term, scoring six goals in 15 games before a foot injury prevented him from extending his spell on Tyneside.
The former Nottingham Forest man is now back to full fitness and he is weighing up his options when he becomes a free agent.
A number of foreign sides from Greece and Turkey are thought to have sounded out Harewood about a move, while several Championship teams are also chasing the striker.
Harewood's agent, Phil Sproson, has confirmed the player will depart Villa and that he is already talking to interested clubs at home and abroad.
"Marlon will be leaving Aston Villa for pastures new as he is free agent in the summer," Sproson told skysports.com.
"I am actively speaking to two overseas clubs and also a number of Championship clubs in England.
"Marlon is back to fitness and he will be a smashing signing as a free agent.
"We will sit down and look at all the offers that come in for him and then decide what is best for Marlon and his family."