Where available, click on each player's name for a link to the original release detailing his acquisition.
All years are categorized by the season in which the player was first available for selection by the Union, i.e. a trade in the offseason after the 2013 campaign would be categorized as "2014."
| Season | 2012 | 2013 | 2014 | 2015 | 2016 | 2017 | 2018 | 2019 | 2020 |
| SuperDraft | Raymon Gaddis | Andre Blake |
|
Jack Elliott | |||||
| Homegrown |
|
|
Anthony Fontana | Brenden Aaronson | Jack de Vries
|
||||
| Trade |
|
Warren Creavalle |
|
Joe Bendik | |||||
| Signing (Discovery, Free Agent, etc.) |
|
Alejandro Bedoya
|
Cory Burke | Aurelien Collin | Alejandro Bedoya |