The holders were wobbly in a 0-0 draw with Venezuela in their opening Group B match in La Plata on Sunday.
"As we have been looking at variations we're going to wait [to make a decision] just before the match," Menezes said on Thursday after trying out a probable first team without Robinho and Ramires.
"I said that in the second week [of the tournament] I'd look at variations to see how the team responded," he said as he considers the option of playing 2010 World Cup veteran Elano from the start in place of Ramires.
Menezes appears to also be thinking of fielding gifted 18-year-old Lucas instead of Robinho up front as he ponders two changes that conform with substitutions he made against Venezuela.
"From the national team as a whole I expect an improvement with more continuous production. To make individual criticism now confuses more than it helps," he said.
There were intermittent hints of the traditional Brazilian attacking style Menezes is trying to revive against Venezuela, the weakest team of the group on paper.
A goal has yet to be scored in the group after Paraguay and Ecuador also finished up goalless in Santa Fe on Sunday.
The Ecuadoreans travel to Salta to face Venezuela on Saturday.
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