On the surface, the reason was simple: every player and coach in uniform on both sides of the field wore No. 42 on his jersey to honor Jackie Robinson on the 63rd anniversary of the day Robinson broke baseball's color barrier and suited up for his first big league game with the Brooklyn Dodgers.
But in a very real sense, the original No. 42, Robinson himself, continues to make his impact on the game. Despite the "uniformity" of the jersey numbers, and the fact that only one African-American started Thursday's game in Colorado, the national pastime was catapulted to the front lines of the Civil Rights era when Robinson took the field for the Dodgers, and baseball was forever changed by the slow but certain integration of the sport at a time when "separate but equal" was the law of the land, from schools to lunch rooms, from the big leagues to the Negro Leagues.
"I always try to put myself in his position," said Rockies hitting coach Don Baylor. "I had to integrate an all-white school when I was in the seventh grade. Man, that was tough. So I can imagine trying to play professional baseball at the level that he played at. He's pretty special to me, what he accomplished and what he had to go through."
Baylor, the Rockies' first manager (1993-1998) and a former Mets bench coach (2003-2004) has a perspective that younger players can't quite grasp. As a young child while Robinson was playing in the big leagues, Baylor could see this universal role model turning impossible dreams into reality in each morning's box score.
"My mom and dad talked about him, and my grandmother," Baylor said of his memories of Robinson. "It was a special time. So many players should be thankful for that time, black or white. He transformed a lot of things. Today, guys kind of take for granted that black guys and white guys shower together, play catch together and stay in the same hotels. They don't think about it."
It's an ironic sign of progress that modern players are in danger of taking the game's integration for granted, but men of a generation or two beyond their playing days still recognize how dramatically the landscape of baseball and society has changed in their lifetime.
"I wouldn't be in the position I'm in if it were not for Jackie Robinson and his pioneering and his groundbreaking presence," Mets manager Jerry Manuel said. "What we have to do is we have to continue to kind of recruit African-Americans back into our sport. I think we're missing a little bit of that ingredient, that spice that could be added. It's a beautiful game, and a lot of cultures play this game. I just hope that our culture doesn't completely miss out in the future."
For Dexter Fowler, the Rockies' second-year centerfielder and the only African-American starter in Thursday's game, the significance of those who came before was not lost.
"It's an honor," Fowler said of the opportunity to don Robinson's jersey number once a year when Major League Baseball takes it out of retirement to honor the legendary Dodger. "The stuff he's done for the game -- you get chills putting on the jersey."
His own manager, Jim Tracy, sees the day as brimming with personal significance, both as a former Dodgers manager and as a baseball lifer who takes the kind of monumental impact Robinson made in proper perspective.
"I've been a student of the game and a rat, so to speak, for a long, long time, so the history of the game is very, very important to me," Tracy said. "And the people that basically paved the way to set up a beautiful day like we've got today and another opportunity to be involved in a Major League game, that stuff is real important to me.
"I managed the team that he broke in with for five years, so I know all about Jackie Robinson and what he went through. And so there's a hell of a lot of respect for what he did and some of the barriers that he helped break to make this game and help this game be as special as it's become, believe me."
Though Manuel and Tracy came a little after Baylor in their arrival as young professional baseball players, Baylor got in the game in time to see Robinson at one of his first Spring Training camps, when Baylor was coming up in the Orioles organization in the late '60s and early '70s. Robinson, who died in 1972 at the age of 53, wore the scars of his battles with grace and courage."I crossed paths with him once in Spring Training, but I was too young to even go up to him," Baylor said. "I didn't have the status. He was just kind of crossing the field. He had a lot of gray hair from a lot of worry. He had diabetes. Just a lot of health things probably brought on because of stress. I think of that part of it too. I know his wife Rachel very well, and their daughter Sharon. Any time they ask me to do anything for the Jackie Robinson Foundation, I do it."
On Thursday, Major League Baseball asked its players and coaches to honor the man by donning his number. Come Friday, the tribute continues, in the subconscious, perhaps, but in the very real legacy embraced by everyone from Baylor to Manuel, from Fowler to David Wright, from Jose Reyes to Jorge De La Rosa. The culture, the quality, and the very grain of their game honors the memory of Jackie Robinson.
Owen Perkins is a contributor to MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.