Both players are preparing for the NFL draft and are expected to be high selections. Neither is likely to enter the CFL. But if plans change in the coming years, Mayfield's rights belong to the Toronto Argonauts. Jackson's rights are owned by the British Columbia Lions.
The CFL has long used a method known as a negotiation list, rather than a draft, for allocating American players. Each team can claim up to 45 players and retain their rights for as long as desired. When Americans want to play in the CFL, they must negotiate exclusively with the team that owns their rights.
The list has historically been kept secret, but the league changed its policy this year to allow for a partial release of up to 10 names per team.
Former NFL quarterback Johnny Manziel was not among the 10 players announced by the Hamilton Tiger-Cats, but he is known to be on their list and spent months in negotiations with the team this winter. He currently plans to participate in The Spring League, a domestic developmental league based in Austin, Texas, but has not ruled out playing in the CFL.
During a Twitter conversation with CFL star Duron Carter, son of NFL Hall of Fame receiver Cris Carter, Manziel said in part: "If that's the path I choose, TRUST ME, I'm gunna let it fly."
Hamilton did acknowledge that former NFL quarterback Robert Griffin III remains on its negotiation list. Another former NFL quarterback, Colin Kaepernick, is on the Montreal Allouettes' list.