Mari is captain of NAC this season and has attracted Premier League enquiries.
Though an ankle injury ruled him out in recent weeks he is due to return to face Ajax this weekend.
The 24 year-old was named in the Eredivisie's team of the month for October.
Signed by City from Gimnastic de Tarragona in 2016, Mari was sent out on loan to Girona last season before moving to Holland for this campaign.
The Daily Mail says his progress has attracted interest from top-flight and Championship clubs in England.