Angola striker Flavio and defensive midfielder Stelvio are doubtful for Sunday's African Nations Cup opening game against Mali, coach Manuel Jose said on Tuesday.
Flavio was injured in the 1-1 draw with Gambia in Portugal on Sunday in Angola's last warm-up match before the start of the tournament which it is hosting.
Stelvio picked up his knock in another warm-up international against Estonia on December 30.
"It is my big concern that Flavio recovers and is available to play against Mali," the coach told reporters on the team's return to Angola after a month-long training camp in Portugal.
"He, together with Stelvio, are important to our starting lineup because we don't have any stars in our team and need the key elements of our collective."