Baseball Question

Following an infield out, and when the bases are empty, the ball is tossed around the infield, ending up with the 3rd Baseman who tosses it back to the pitcher. Why is the 1st Baseman excluded?

Because the first baseman is involved in many plays and doesn’t need to stay warm between at-bats. Also, the first baseman isn’t called on to make many throws. Also, tradition.