For example, the Cubs made an exception to their long-standing policy of only retiring Hall of Famers numbers a few years ago when they retired Ron Santo's No. 10. The Astros, in contrast, have retired the numbers of nine former Astros, only one of which is currently in the Hall of Fame.
The No. 42 was retired for all teams by Major League Baseball in 1997 in honor of Dodgers legend Jackie Robinson.
Gonzalez played for six teams over parts of 19 years in the big leagues, collecting 2,591 regular-season hits.
During his eight years with the D-backs from 1999-2006, Gonzalez, who wore No. 20, was a fan favorite for not only his play on the field, but his community involvement.
In 2001, he blasted 57 home runs, but the hit he will be most remembered for was a bloop single to left off the Yankees' Mariano Rivera to drive home the game-winning run in Game 7 of the 2001 World Series.
Gonzalez left the D-backs as a free agent following the '06 season and played one year each for the Dodgers and Marlins before retiring to take a job as special advisor to Hall.
Since taking the job, Gonzalez has been involved in a number of projects for the organization and is regularly in his Chase Field office. He has made trips to talk with the team's Minor League prospects, visited the team's academy in the Dominican Republic and participated in the D-backs' Fantasy Camp.
This spring, he will spend some time in uniform working as an instructor.
"Gonzo has been a tremendous addition to our team off the field," Hall said. "He is willing to do anything we ask of him and continues to bring fresh and creative thoughts to nearly every department. He cares deeply about this organization, its fans and its employees, and has proven that with his hard work and positive influence."
No player has worn No. 20 since Gonzalez left the organization. Right-hander Jeff Suppan wore No. 20 during the 1998 inaugural season.