![MLB Jersey Numbers on Twitter: "RHP Luis Castillo will wear number 21. Last worn by OF Steven Souza, Jr. earlier this season. #Mariners https://t.co/MBBkzwhGbF" / Twitter MLB Jersey Numbers on Twitter: "RHP Luis Castillo will wear number 21. Last worn by OF Steven Souza, Jr. earlier this season. #Mariners https://t.co/MBBkzwhGbF" / Twitter](https://pbs.twimg.com/media/FZAsdsOXwAAi4L_.jpg)
MLB Jersey Numbers on Twitter: "RHP Luis Castillo will wear number 21. Last worn by OF Steven Souza, Jr. earlier this season. #Mariners https://t.co/MBBkzwhGbF" / Twitter
![All Pirates Wearing #21, Rest of MLB Wears Patches in Honour of Roberto Clemente – SportsLogos.Net News All Pirates Wearing #21, Rest of MLB Wears Patches in Honour of Roberto Clemente – SportsLogos.Net News](https://content.sportslogos.net/news/2020/09/roberto-clemente-pirates.jpg)
All Pirates Wearing #21, Rest of MLB Wears Patches in Honour of Roberto Clemente – SportsLogos.Net News
![MLB Jersey Numbers on Twitter: "1B Matt Adams will wear number 18. Last worn by OF Lane Adams earlier this month. #Braves https://t.co/7uMa7a71KM" / Twitter MLB Jersey Numbers on Twitter: "1B Matt Adams will wear number 18. Last worn by OF Lane Adams earlier this month. #Braves https://t.co/7uMa7a71KM" / Twitter](https://pbs.twimg.com/media/DAXDeWSXUAEjZzB.jpg)
MLB Jersey Numbers on Twitter: "1B Matt Adams will wear number 18. Last worn by OF Lane Adams earlier this month. #Braves https://t.co/7uMa7a71KM" / Twitter
![Some MLB Players Wearing #21, All Wearing 21 Patches Today for Roberto Clemente Day – SportsLogos.Net News Some MLB Players Wearing #21, All Wearing 21 Patches Today for Roberto Clemente Day – SportsLogos.Net News](https://content.sportslogos.net/news/2022/09/ROBERTO-CLEMENTE-day-jerseys-21-2022-sportslogosnet-3.jpg)
Some MLB Players Wearing #21, All Wearing 21 Patches Today for Roberto Clemente Day – SportsLogos.Net News
MLB celebrates Roberto Clemente Day as players wear No. 21, call for number to be retired - CBSSports.com
![MLB Jersey Numbers on Twitter: "In addition to the #Pirates' on-field tribute, all Puerto Rican-born #MLB players have the opportunity to wear number 21 on the field for #RobertoClementeDay. https://t.co/ZcROE8K30X" / Twitter MLB Jersey Numbers on Twitter: "In addition to the #Pirates' on-field tribute, all Puerto Rican-born #MLB players have the opportunity to wear number 21 on the field for #RobertoClementeDay. https://t.co/ZcROE8K30X" / Twitter](https://pbs.twimg.com/media/EhgE7KNXYAApaPB.jpg)
MLB Jersey Numbers on Twitter: "In addition to the #Pirates' on-field tribute, all Puerto Rican-born #MLB players have the opportunity to wear number 21 on the field for #RobertoClementeDay. https://t.co/ZcROE8K30X" / Twitter
![MLB Jersey Numbers on Twitter: "Today, players across #MLB have the opportunity to wear number 21 to honor the legacy of the great Roberto Clemente, as MLB celebrates #RobertoClementeDay https://t.co/2kQ2AGbi0D" / Twitter MLB Jersey Numbers on Twitter: "Today, players across #MLB have the opportunity to wear number 21 to honor the legacy of the great Roberto Clemente, as MLB celebrates #RobertoClementeDay https://t.co/2kQ2AGbi0D" / Twitter](https://pbs.twimg.com/media/FcvG4aGWYAYJ8SF.png)