Elano to miss Portugal match
Elano was injured by a heavy tackle in Sunday's 3-1 win over Ivory Coast in Group G and had to be substituted.
The 29-year-old trained separately from the rest of the squad on Thursday for the third day running.
"We are going to protect Elano," Dunga told reporters.
Dani Alves, who plays right-back for Barcelona but often steps into midfield for Brazil, is likely to replace Elano while Julio Baptista is favourite to stand in for the suspended Kaka.
"Julio played in this role in the Copa America in 2007," said Dunga. "Kaka has a burst of pace which few other players possess, Julio has a good shot from long-range and is a potent force in midfield.
Brazil have already qualified for the last 16 after winning their first two matches in the section.