The full-back is spending the season on loan at Alaves, but reports ahead of this weekend's Madrid derby in LaLiga have suggested that Zinedine Zidane's side could trigger a release clause in his contract.
But Cerezo says such rumours are common place ahead of clashes between the rivals and vowed to fight to keep the France youth international when he returns to Atleti.
"Whenever we are about to play a derby, something similar happens," Cerezo told El Transistor. "People should be more serious. We do not waste time with such stuff.
"Nobody has asked us about Theo, about clauses, nothing at all. We do not know anything about this.
"If Madrid ask us about Theo, the answer would be energetic and determined. Theo is our player - on loan at Alaves, but our player."
Hernandez has impressed in 25 Liga appearances for Alaves this season, but is yet to feature for Atleti, where his brother Lucas Hernandez is in the first team squad.