Romero was forced off during Tottenham's 2-2 draw against Manchester City due to an illness, taking the club's list of absentees for fitness reasons into double figures.
Tottenham boss Thomas Frank has endured a difficult first season in charge, in part because of the number of key personnel sidelined for long periods.
The north Londoners have won just two of their last 15 Premier League games and sit in a disappointing 14th place.
Even though Tottenham signed England midfielder Conor Gallagher from Atletico Madrid midway through January, they sold last season's leading scorer Brennan Johnson to Crystal Palace.
Moments after the winter transfer deadline closed, Argentine defender Romero took to social media to air his frustration at their lack of recruits.
"Great effort from all my teammates yesterday, they were incredible," he said on Instagram.
"I wanted to be available to help them even though I wasn't feeling well, especially since we only had 11 players available - unbelievable but true and disgraceful.
"We'll keep showing up and taking responsibility to turn this around, working hard and staying together. All that's left is to thank all of you for being there and for always supporting us, the fans."
Romero's social media blast was liked by several Tottenham team-mates, including Pedro Porro, Xavi Simons and Dominic Solanke.
Tottenham made failed approaches for Ghana forward Antoine Semenyo, who joined Manchester City from Bournemouth, and Liverpool defender Andy Robertson.
They did announce the loan signing of Hearts teenager James Wilson on Monday with the option to make the move permanent, but the forward will only feature for the U21 squad initially.