The Brazilian is usually third choice centre-back at BVB, behind Subotic and Mats Hummels, but will now fill in for the injured Serbian who tore a calf muscle in a recent friendly.
Santana told Bundesliga.de: "The news of Neven’s injury was of course sad. But hiis misfortune is now my luck because I can play. But I do not see it from this point. Because every time I play I want to help the team as best I can.”
Dortmund are currently third in the Bundesliga and sit 12 points behind leaders Bayern Munich, with Santana concerned at the number of goals his side have conceded.
"We conceded too many goals before the winter break. We want to make that a lot better in the second half," he stated.
Santana also spoke about new signing Nuri Sahin, who played for the club before his move to Real Madrid in 2011.
"Nuri is a brutally good player. We knew what skills he has and how he plays," praised the defender.
"We do not see Nuri as another competitor. We see that with Nuri we have more quality in the team."