By SABC Sport
27th December 2023
Romero only returned from a three-match suspension at the beginning of December but is now set for another spell on the sidelines.
The Argentina international sustained the injury during last weekend's 2-1 victory against Everton and a scan this week has revealed a hamstring strain.
Speaking ahead of Thursday's trip to Brighton, Postecoglou said: "Not so great with Romero.
"He had a scan the other day and has got a hamstring strain. We are looking at probably four or five weeks for him.
"Disappointing to lose him, for sure. We obviously missed him with the suspension and now we've just got him back and he steadied things up.
"Now he will be missing again for quite a chunk of time."
Romero's previous absence was compounded by centre-back partner Micky van de Ven being out with a hamstring injury.
Summer signing Van de Ven sustained the issue in the 4-1 loss to Chelsea in November, but is close to a return and revealed at the PDC World Darts Championship last week that he could be back training in two weeks.
Postecoglou was cautious with a timeline, although admitted the trip to Manchester United on January 14 could be a comeback date for Van de Ven.
"He is getting closer," Postecoglou confirmed.
"We will see him some time in January. I don't think Burnley but Man United on the 14th potentially
"I don't look at comeback dates until I see them training with us and he hasn't been part of the group.
"He is not due to be part of the group this week so we'll see how he is going at the end of this week. Once they start training with the group, that's when we start thinking about if they are available.
"He is at the tail end of it, for sure and at some point, middle of January he could be available but how we use him after such a long absence will be depending on where he is at."