Tottenham Hotspur have reportedly identified Uruguay international Sebastian Caceres as their top defensive target for the January transfer window.
Cristian Romero, who is currently suspended, and Eric Dier are the only other natural first-team centre-back options at Postecoglou's disposal, further highlighting Tottenham's need to strengthen in January.
The report adds that Spurs have initiated negotiations with the Mexican club and submitted a formal offer earlier this month.
Caceres is said to have given the green light to join Tottenham, who are expected to step up their pursuit of the 24-year-old in January.
Born in Montevideo, Caceres has spent nearly four years with Club America, making a total of 112 appearances across all competitions.
Caceres is yet to lift silverware in his professional career, but he is widely regarded as one of the best defenders in the Mexican top flight, while he has also impressed at international level with Uruguay.
The 5ft 11in centre-back represented Uruguay from Under-18 to Under-23s level before making his senior debut in September last year, and he has since earned nine caps for his country.
Caceres has been a first-team regular since the arrival of new head coach Marcelo Bielsa, playing every minute of Uruguay's 2026 World Cup qualifying campaign.
Uruguay have won each of their last three South American qualifiers over the last two months with Caceres in the side, beating Brazil, Argentina and Bolivia without conceding a goal.