The Daily Mail is reporting that Manchester City are keeping close tabs on Virgil van Dijk and William Carvalho.
The Citizens are aware they will soon need to recruit long-term replacements for Vincent Kompany and Yaya Toure, and the likes of van Dijk and Carvalho appear to be top of their hit-list.
The Dutch defender has largely impressed since joining Southampton from Celtic, and Man City scouts have regularly watched him this season.
If they decide to cash in on their star player, the Saints will demand a much higher fee than the £11.5 million they paid for him a year and a half ago.
Meanwhile, the Citizens have also been keeping close tabs on William Carvalho for quite some time, but with Yaya Toure returning to the squad, they are unlikely to make a move midway through the season, but will rather wait until the summer transfer window.