In an interview with Thomas Bassinger of the Tampa Bay Times, XFL commissioner Oliver Luck said he believes the quarterbacks in the league "are better" than Manziel at this point in his career.
The XFL announced quarterback assignments for its teams on Oct. 15, with Landry Jones (Dallas Renegades), Cardale Jones (DC Defenders) and Aaron Murray (Tampa Bay Vipers) among the notable names in the league.
Manziel wasn't eligible for the league's inaugural draft in October because he didn't enter the draft pool. The 2012 Heisman Trophy winner previously said he'd welcome the chance to play for the Houston Roughnecks.
"It's a stone's throw from College Station," Manziel told reporters at a TriStar collectors show in June. "A lot of Aggies drove from Houston to College Station. Houston's a great city that'll always be near and dear to me."
When Vince McMahon announced the XFL's return in January 2018, Manziel tweeted at the WWE CEO with the XFL 2020 hashtag.
Since being released by the Cleveland Browns in March 2016, Manziel has spent time in the CFL with the Montreal Alouettes and most recently with the Memphis Express in the Alliance of American Football. The 27-year-old appeared in two AAF games, attempting eight passes before suffering a concussion on March 30 against the Orlando Apollos.
The XFL season kicks off on Feb. 8 with the Seattle Dragons taking on the DC Defenders.