It will mark a special moment in the life of the young baseball player from Indiana, who is an avid fan of the Yankees and refuses to let physical challenges limit his participation in the game.
The boy's mother, Amanda Haag, noticed his passion for sports and competition from a young age, and watched him work each day to prove his abilities to his coaches.
By age 8, he was pitching. As he got older, he tried different sports, playing tackle football last fall, and he is currently a member of his school's basketball team.
Haag told ABC News ahead of Sims' first pitch on Sunday that her son is not nervous. His mother added that her son will likely "think, 'This is really cool just throwing from a Major League pitcher's mound.'"
Haag continued that Sims has always carried a "Watch me. I can do this, and I don't tell me I can't" attitude and that he seemed "laid back" leading up to the game.
Sims was born without hands and legs. He can still bat, run the bases and throw, competing and excelling with other kids his age.
Along with his hard work and determination, Sims also credits the efforts and assistance of the Challenged Athletes Foundation, an organization that provides opportunities to people with physical challenges.
Sims does not sound too worried either. The longtime Yankee fan said he's been to Yankees spring training in Florida and has even stepped on the field at the facility a few times.
Still, he admitted that it will be a little different standing in front of a regular season crowd, but said he's been practicing by throwing "a lot of long throws to see how accurate I can get it."
On Sunday, Sims and Haag will take their first trip to the Bronx to throw out the game's first pitch. The Yankees host the Orioles at 1:05 p.m. ET.