The Mexico international has been disappointing since his £16 million summer move to East London and has only netted four goals from 21 games in all competitions.
Irons boss David Moyes played him in Sunday's 0-0 FA Cup draw at Shrewsbury Town in a selection which says a lot about how important Hernandez is to him.
The 29-year-old has only started one Premier League game since Moyes replaced Slaven Bilic at the beginning of November.
And Mariner believes that he might well leave the London Stadium before the winter transfer window shuts.
He told ESPN: "You looked at him the other day in the cup but he's not getting the service that Chicarito requires.
"I think if Andy Carroll could stay fit, I think he's the type of centre-forward Moyes wants to build around. For Chicarito, I think it's a hit. He's got to get out of there."