Costa is an injury doubt for the capital outfit after limping out of the first leg which finished 1-1 last week, but Martino is preparing for an Atletico side with the Spanish international involved.
"He's the kind of player coaches take as long as possible over to see if they can play or not, even if they aren't in the best of shape," Martino told AS.
"It's too early to speculate as to whether he'll play or not. We're preparing ourselves to play Atlético Madrid with all footballers they have."
Each of the four meetings between the two sides this season have ended in draws.