At least one member of every team followed Griffey's lead. Some entire rosters donned the 42. The league is encouraging another un-retirement of the number on the 61st anniversary of Robinson's historic feat.
"All players have the option. It's entirely up to them," Selig told MLB.com on Monday. "Candidly, I hope they all do it."
Like last year on April 15, the Reds will be playing the Cubs at Wrigley Field.
"I will be wearing it," Griffey said.
So will Reds manager Dusty Baker, who was informed of the Commissioner's comments.
"That'd be cool. It's appropriate and necessary," Baker said.
Griffey normally wears No. 3, while Baker has made No. 12 a fixture throughout his playing and managerial career.
Baker was out of baseball last season and did not get to take part in the league-wide tribute to Robinson. Baker, a former Dodgers player, has great appreciation for Robinson's contribution to baseball.
"I have Jackie all over my house," Baker said. "I have a special Jackie Robinson wall in my memorabilia room."
Introduced in 2004, Jackie Robinson Day was created to honor the enduring impact of Jackie Robinson and his legacy as the first African-American player to break the Major League color barrier. Robinson played his first Major League game at Ebbets Field on April 15, 1947, as a member of the Brooklyn Dodgers. In honor of the 50th anniversary of Robinson breaking the Major League color barrier in 1997, Robinson's uniform number 42 was retired throughout the Major Leagues.
Robinson's memory lives on today in initiatives such as the Jackie Robinson Foundation, which was founded by Rachel Robinson in 1973 to provide education and leadership development opportunities for minority students with strong capabilities but limited financial resources, as well as Breaking Barriers, which utilizes baseball-themed activities to reinforce literacy skills, mathematics, science and social history in addition to addressing critical issues of character development, such as conflict resolution and self-esteem.