Manchester City are ready to reignite their interest in Southampton's Virgil van Dijk, Goal has learned.
The Premier League leaders are also considering a move for Real Sociedad's Inigo Martinez, and are hopeful of signing one of the two during the winter transfer window.
City made Van Dijk their top centre-back target during the summer, but were dealt a blow when he elected to join Liverpool, only for that move to collapse and the Dutchman to stay at St Mary's.
Goal understands that Liverpool will also try to sign the 26-year-old during the January transfer window, and it can now be revealed that City are seriously considering a rival offer.
City targeted several other central defenders after missing out on Van Dijk, including Leonardo Bonucci, Jonny Evans and Martinez, but were ultimately unsuccessful in their attempts to reinforce the position.
And following injuries to Vincent Kompany and John Stones, Pep Guardiola has convinced sporting director Txiki Begiristain and CEO Ferran Soriano that defensive reinforcements are required if the Blues are to continue fighting on all fronts for the rest of the season.
The Blues have subsequently made a new centre-back their top priority, and are now weighing up the merits of both Van Dijk and Martinez.
Sources have told Goal that Van Dijk is the preferred option, as Guardiola and his employers consider him capable of slotting seemlessly into the City back line and handling high pressure matches both domestically and in Europe.
There are lingering concerns regarding how he would react if he does not play regularly once Kompany, Stones and Nicolas Otamendi are all fit.
That is not thought to be an issue for Martinez, 26, who City staff believe would be more accepting of a squad role. The Spain international would also be a cheaper option than Van Dijk, given his €32 million release clause.
But there are understood to be reservations over his ability to immediately adapt to his new surroundings and handle the biggest matches during the run in.
City are expected to make enquiries regarding both men in the coming weeks.
The Blues remain interested in Alexis Sanchez, their overall top summer target, but any January move is once again dependent on whether Arsenal will do business with their rivals.
The Chilean is out of contract in the summer and while City are confident he still wants to move to the Etihad Stadium, they are concerned that foreign clubs can make legal approaches from January 1.
Although City had agreed personal terms with Alexis early last summer, they were still spooked by Paris Saint-Germain's rumoured interest in July.