Real Betis are interested in keeping Tristan in La Liga but Depor president Augusto Cesar Lendoiro appears more keen on selling to a Premiership club because they will offer a higher transfer fee.
Meanwhile, Radhi Jaidi has urged Bolton Wanderers boss Sam Allardyce to take a close look at Tunisia teammate Ziad Jaziri.
Striker Jaziri, 27, is keen on a move to England from French club Troyes.
And Bolton star Jaidi said: "He has pace and strength and would flourish in the Premiership."