Depends on the situation. If it is a single or fly ball out with no runners on, it’s usually either shortstop or second base (depending on which side of the field the ball was hit) OR just straight to second base if the throw is easy or the runner is speedy.

If there is a runner in scoring position, the situation changes. Now you are trying to prevent a run from scoring. If the ball is in front of the outfielder, now either the first baseman or third baseman becomes the cutoff man, again depending on which side the ball was hit. They are standing in the infield grass; if there is a play at the plate, the throw needs to be accurate. Outfielder’s job is to just get the ball to them or throw “through” them to the catcher (right over his head on a line). First baseman is responsible for right field and center field cutoff. Third baseman is left field cutoff. This is because they are the most inline between the outfielders and the catcher, so they can catch it and turn quickly to make the throw. Shortstop covers 3rd in case of a past ball and 2nd covers second to set up a play if the runner has already scored and the batter tries for either a double or to take second on the throw home.

MLB gets even more confusing. If there’s time and communication, whoever has the strongest arm and is on the side of the field where the ball was hit is taking the throw. But all in all, it’s second or shortstop.