The Brazilian has been limited to just 90 appearances for the Bianconeri since joining from Bayern Munich in 2017.
Costa admits his many physical ailments have affected his confidence, to the point that he’s considered retiring.
“There are times when I think: ‘Can I still play?,’” he told The Players’ Tribune.
“[That’s] because I go out on the pitch and get injured again. Then, when I watch it on TV, I remember this is my passion and that I can still play at a high level.
“This is what keeps me alive, I know football comes easy to me. It has nothing to do with money or being famous.
Despite the many problems, Costa was able to joke that he’s had more scans than minutes on the pitch.
“The point is to do what you enjoy and have fun doing it,” he added. “That’s my objective. I joke with Alex Sandro that I’ve had more scans than I’ve played games.
“People say ‘Douglas has the potential to be one of the best in the world, but injuries are holding him back.’ That annoys me.
“I have the potential to be a top player, but for reasons out of my control I can’t be.
“Every time I get injured, I ask myself: ‘What did I do wrong?’ I wonder why I can’t play consistently. It’s something that hurts me.
“Therefore, I asked for help. I don’t know if you’ve heard of a mental coach. They’re not a psychologist, but they show you how childhood facts can still affect you.”