By Lyle Spencer For Latin American players, Roberto Clemente’s No. 21 always has held special meaning. The magical number in Giants history is Willie Mays‘ 24. Reigning NL MVP Buster Posey is making No. 28 immensely popular in the AT&T Park stands.
From: http://mlb.mlb.com/news/article.jsp?ymd=20130411&content_id=44522068&vkey=news_mlb&c_id=mlb