• Players Weekend gear available at MLBShop.com
For O'Day, that name will be Odachowski, the last name his father grew up with. The name change came as a tribute to his grandmother, who essentially raised O'Day's father and his brothers. His grandfather passed away at a young age after returning from World War II, leaving O'Day's grandmother to raise three boys on her own. When his grandmother would go to work at Chicago's Montgomery Ward, she would make it easier to pronounce by going by Mrs. Odach (with the "ch" part silent in the Polish community).
O'Day's father and one of his brothers changed their last names to O'Day as a tribute to their mother when they got married.
"I love my last name, obviously it's what my dad chose, but I still have family who goes by Odachowski," O'Day said. 'So, it's just cool to be able to put that on the back of my jersey for once."
Orioles center fielder Adam Jones -- who wanted to wait to unveil the specifics -- is going with a nickname his mother gave him as a young boy.
"She still calls me it to this day," he said. "She only called me it when I was in trouble, so since I heard it often, I must have been in trouble a lot."
Jones will pay further tribute to his mother, as well as his wife and deceased grandmother, by putting their names on his uniform patch.
The special patch will be on the sleeve of every player during that weekend, showing the progression of a child evolving into a Major Leaguer.
"Patches were tough [to pick a name] because we all had people who were important to getting us to where we are," O'Day said. "If you didn't play youth baseball, there's no way you could play Major League baseball, so there's a lot coaches that I'd love to put all their names on there. But I just went with Mom and Dad because of all the practices they had to take me to and all the time they spent, obviously wouldn't be here without them."
All of the game-worn, Players Weekend jerseys will be auctioned at MLB.com/auctions with 100 percent of net proceeds donated to the MLB-MLBPA Youth Development Foundation. The foundation is a joint effort established in July 2015 by MLB and the MLBPA that focuses on improving the caliber, effectiveness and availability of amateur baseball and softball programs across the U.S. and Canada.
"Obviously it's something that's different. It's cool to get further background on the individual [player]," Jones said of the jerseys, which will be first worn by by the Pirates and Cardinals during the MLB Little League Classic on Sunday, Aug. 20.
"People are going to have nicknames, patches, people they are representing that have helped push them in their career. I think it's beneficial to see what drives the individual, not just the game, but individuals that drive us to do what we do as people and baseball players."
Here's a list of nicknames that some Orioles are expected to sport on the back of their jerseys on Players Weekend:
• Manny Machado: "MR. MIAMI"
• Jonathan Schoop: "MAMBA"
• Tim Beckham: "SWAGGY T"
• Chris Davis: "CRUSH"
• Welington Castillo: "BEEF"
• Chris Tillman: "TILLY"
• Ubaldo Jimenez: "BIG U"
• Zach Britton: "BRIT"
• Brad Brach: "B-RAD"