Years and years of practice and a whole lot of skill.
you have to keep studying baseball and become an excellent player then you go to the miner leagues and if you are a good player, managers of mlb teams will have to see you play then decide if they want you for their team. If they choose you, then you will have become a part of the mlb.
Because he is a MLB player for the Seattle Mariners.
Lifting weights, Natural talent, practice, practice, practice
MLB player Curtis Granderson throws right.
MLB player Adam LaRoche bats left.
About 1% of the population become part of professional sports. It takes talent, focus, and some luck to join a team.
MLB player Aaron Loup throws left.
MLB player Jose Ramirez can bat right or left (i.e. he is a switch hitter).
MLB player Abraham Almonte throws right.
MLB player Bryan Holaday bats right.
MLB player Anthony Rizzo throws left.
MLB player Brian McCann throws right.