In Maniac Magee by Jerry Spinelli, what kind of career does Grayson have in the Minor Leagues? How does Grayson appear different when he tells Jeffrey he had been a pitcher?

Grayson had experienced a fairly long career as a Minor League Baseball player.  He had played as a pitcher on several different baseball teams.  He had once had a chance to impress a scout for a team that was "one short step from the Majors" (Maniac Magee, Chapter 25).  Instead of impressing the scout, Grayson had pitched a horrible game.  His chances of someday playing Major League Baseball were over.  He continued to play on Minor League teams until he was about forty.  His last team was in Mexico.  The years had left him unable to play with the necessary skill.  He retired from baseball, and became a janitor.
When Grayson told Maniac Magee that he had been a pitcher in his younger years, the boy was shocked.  Maniac had never expected Grayson to reveal such a secret.  Grayson was not a "rickety, whiskered worm chow" (Chapter 25).  Instead, he had been a baseball pitcher for many years.  Maniac was in awe.  He begged Grayson to tell stories from his baseball days.