O’Neill is after Boro defender David Wheater while Turkish play-maker Tuncay would also be of interest.
Defender Justin Hoyte could also come into the equation.
Harewood’s Villa career is drawing to a close after two unhappy years.
The former West Ham player, who cost Villa £4million, endured what is best described as a ‘wasted’ season last year, making six substitute appearances equating to less than an hour’s football in the Premier League.
Harewood, who turns 30 in August, has one year remaining on his contract and is likely to be valued at around £1.5million.