Despite having only four first-team centre-backs at the club (and with new signing Jamaal Lascelles at Forest for the rest of the season), Newcastle are about to let Mapou Yanga-Mbiwa leave the club, with a loan move to Roma in the offing. That deal would include a permanent option - though only because it is a legal requirement - but will leave Newcastle woefully short of options. In effect, the decision to let him go is weakening arguably the weakest defence in the league, and that cannot stand. The suggestion then - thanks to recent links with Toby Alderweireld among others - is that Newcastle will now be moving to bring another defender in to cover the outgoing Frenchman. Right now, the most enduring link is to Man City's Serbian stopper Matija Nastasic who is available for a move. According to Sky Sports, the Magpies are locked in battle with Arsenal over a move - which could in fact be a permanent one - for the defender whose opportunities at City have been further limited by the arrival of Eliaquim Mangala for £32m from Porto. Would you be happy with Nastasic as a replacement for Yanga-Mbiwa? Share your thoughts below in the comments thread.