The 23-year-old started his career as a winger but has flourished since Benfica coach Jorge Jesus moved him back, making 24 appearances and providing eight assists for a team that could clinch the championship this weekend.
Queiroz will next month announce his 23-man squad for the finals in South Africa in June and his assistant Agostinho Oliveira said Coentrao was being considered.
"The list (squad) is still open. Fabio Coentrao will continue to be assessed especially as he is playing in the left back position," Oliveira told reporters.
The role has been problematic for Portugal coaches in recent years.
During the World Cup qualifiers Queiroz played Malaga midfielder Duda at left back.
Queiroz's predecessor Luiz Filipe Scolari also struggled to find a natural left back and had to move Chelsea's Paulo Ferreira there, a move which may not be an option this time due to his club mate Jose Bosingwa's long-term injury.
"We're following (youngsters) Fabio Coentrao, Rui Patricio and Yannick Djalo. They may play in the World Cup but they are also the base for our team for Euro 2012," Queiroz told a news conference last month.
Patricio, 22, plays in goal and his Sporting team mate Djalo, 23, is a winger.
Queiroz called up Coentrao for the qualifying playoffs against Bosnia in November, giving him his debut in the first leg, and said the player's development should be seen as an example for others.
