The number 22 was not Andrew McCutchen's first choice.
He wanted to wear No. 24 in honor of his idol, Ken Griffey Jr., but Tom Gorzelanny had it when McCutchen was called up to the majors in June of 2009. McCutchen planned on changing his number for his second year in the majors, but by that point he had seen people wearing his No. 22 jersey around the ballpark. He loved the sight and knew he couldn't change it.
Since then, no Pirate besides McCutchen has worn No. 22, even in the five years since he was traded.