The Sun reports that Guardiola "has been keeping tabs on Real Sociedad defender Inigo Martinez, who had been a target for City in the summer.

Spain international Martinez, a central defender who can also operate at left-back, remains of interest to the leaders, hit by injuries to John Stones and Benjamin Mendy.

The Sun says they "have continued to monitor his performances for Sociedad during the first few months of the season."

And it adds that "the hamstring injury that will keep Stones out for much of the rest of the calendar year has highlighted how short they are in his position."

A move for Martinez could hinge on the success -- or otherwise -- of Vincent Kompany's return from another injury.

But the Sun says Martinez is likely to be of high interest to City in January because of his ability to cover at left-back, with Mendy "likely to miss much of the rest of the season."