[14][15] On April 16, the first player for the 2021 TSL season was announced, as former Syracuse and Dallas Renegades QB Eric Dungey confirmed he will play for the Blues,[16] although he was later accepted tryout invite to Cincinnati Bengals rookie minicamp,[17] and was later signed to their 90-men roster.

[29][10] 39 players with XFL experience were on TSL rosters,[30] and 19 players who participated in the Fan Controlled Football 2021 season (Joseph Putu, Roman Tatum, David Gilbert, Kwadarrius Smith, Curtis Collins, Dominique Martin, Jaylen Flye-Sadler, EJ price, JaMichael Edwards Lott, Deondre Francois, Lawerence Keys, Dwayne Wallace, Donald Boone, LaDarius Galloway, Andrew Jamiel, KaVontae Turpin, Saige Young, Cecil Cherry and Antonio Dawkins).

The league also featured three international players: Kicker Tadhg Leader (Aviators) from the Republic of Ireland, Defensive Linemen Orlovicius Laurynas (Blues) from Lithuania and Wide receiver James Tyrrell from Canada.

Alphas: Vad Lee, Brian Lewerke, Jawill Davis, Kristjan Sokoli, Christian DiLauro, Gabe Holmes, Azeem Victor and Mazzi Wilkins, while Brady White joined before week 4.

Aviators: Keller Chryst, Romar Morris, Malcolm Pridgeon, Lavon Hooks, Mark McLaurin and Irish-born American rugby union player Tadhg Leader,[31] while Vad Lee joined from the "Alphas" before week 5.

Blues: Eric Dungey, Deondre Francois, Fabian Guerra, Davion Davis, Hakeem Valles, David Grinnage, Denzel Rice and Xavier Perston.

[33] Generals: Ryan Mallett, Case Cookus, Devin Gray, Jordan Suell, Sal Cannella, Ethan Westbrooks, Blair Brown, Carroll Phillips, Kamilo Tongamoa, Nevelle Clarke, Malik Gant[34] and Lirim Hajrullahu.

Jousters: Luis Perez, Drew Anderson, Lavon Coleman, De'Lance Turner, De’Quan Hampton, Damore'ea Stringfellow, Donnie Ernsberger, Tejan Koroma, Damien Mama, Bunmi Rotimi, Tomasi Laulile, Christian Sam, Nyles Morgan, Derrick Jones, A. J. Hendy, Shalom Luani, Joshua Simmons, William Likely, Ricky Aguayo, Manoa Pikula and Colton Schmidt.

[39] Terry Shea (Aviators), Ted Cottrell (Blues), Jerry Glanville (Conquerors)[40] and defending champion Bart Andrus (Generals) returned to their 2020 Fall season teams, while Peter Vaas (Alphas) and Kevin Gilbride (Jousters)[41] replaced Steve Fairchild and Chuck Bresnahan (respectively).