A thumb injury has forced a professional Call of Duty player to retire at age 25.

Many professional players train and compete for more than 10 hours a day. Some of them are even able to make millions every year just by playing.

It is not as easy as it sounds to make this kind of money playing video games. There is a lot that you need to give up in terms of physical and mental health.

It was a Tough Announcement for ZooMaa to Make

Thomas 'ZooMaa' Paparatto said in a Twitter statement that he had to retire from the eSports world, saying that walking away from the game 'breaks' his heart.

The 25-year-old player said: "I am stepping down and will no longer compete in competitive Call of Duty for the foreseeable future.

"Not sure if many of you remember, but a few years back while on FaZe, I struggled with weakness in my thumb/wrist and needed surgery."

"Going through that process of getting healthy again was one of the hardest things I ever had to do both physically & mentally, which led to a lot of stress and anxiety."

"Unfortunately, the injury has returned, making it really hard for me to compete at the highest level against some of the best players in the world. Playing through the weakness and pain in my hand just isn't possible anymore."

"I don't enjoy competing when I can't be the ZooMaa everyone knows and loves and feel like it's not fair to myself or to my team to go through all that again, potentially causing more damage to my hand."

The New York Subliners player said that he has met "so many amazing people" through esports, in addition to making many friendships that he will cherish forever.

"It breaks my heart to step away from a game I put my heart and soul into every single day for eight years. Tearing up just writing this, but I don't know what else to do at this point," the young player continued.

"It's been an amazing run... I don't regret anything and I am grateful to have had a long playing career doing what I love to do at such a high level."

ZooMaa's Fans and Other eSports Players Showed Their Support

After thanking everyone in his life for their support, the gamer added: "I'm not sure what the future holds and I will explore all options as I love this game too much to walk away completely. I look at it as one door closing and another one opening."

Many of Paparatto's fellow gamers commented on his post to wish him well. In fact, CoD World Champion Attach commented as well, saying:

"This was difficult to read. I'm so sorry that this happened, Duo. I know you're going to crush it in whatever you decide to do next. It's been an honor to team with you and make so many memories. If you ever need anything, I'll always be here for you, brother."

Bradley 'APG' Laws of Team Envy had something to say, too. He wrote:

"Awful to hear but wishing the best for you in whatever's next and a fast recovery brotha."