The former winners are likely to have one of the strongest attacks at the finals but their defence has come under scrutiny with Romero being criticised for not always commanding his penalty area.
"Romero had a good match and I consider him an excellent goalkeeper who unfortunately is not getting continuity at his club," said Sabella of the keeper's performance in last week's 0-0 draw with Romania in a friendly in Bucharest.
"Apart from the odd injury he has always been in my team ... the position (at the World Cup) is his," the coach told the Radio La Red Argentine station.
Sabella said he had decided on around 90 percent of his 23-man World Cup squad.
Argentina have been drawn in Group F with Bosnia, Iran and Nigeria.
(Reporting by Luis Ampuero, writing by Rex Gowar, editing by Tony Jimenez)
