Tottenham vice-captain Romero will be a welcomed addition to Postecoglou’s side which is currently going through a major injury crisis this season. The 26-year-old will likely prove to be a key player in Thursday's trip to Hoffenheim as Spurs aim to qualify for the next round.
Midfielder Rodrigo Bentancur was also involved in training after suffering a head injury during a 1-0 win over Liverpool earlier this month. He was ruled out of action for a minimum of 12 days due to concussion protocols but will now return for a chance at European football.
The bad news for Postecoglou is that goalkeeper Antonin Kinsky, Djed Spence, Sergio Reguilon and South Korea attacker Yang Min-hyeok cannot play on Thursday as they are not registered in the club's league phase squad for the Europa League.
Other key members of the squad including Guglielmo Vicario, Micky van de Ven, Destiny Udogie, Yves Bissouma, Wilson Odobert, Brennan Johnson, Timo Werner and Dominic Solanke are also all ruled out due to injury.
A victory at Hoffenheim would boost Tottenham’s chances of a top-eight finish in the Europa League and now with the return of Romero and Bentancur, they may have the edge over the German side despite their depleted squad.