The Spanish striker has only managed six goals in 19 games for the Hammers since he signed from Arsenal a year ago.
The Sun claims West Ham are happy to accept a cut price deal if it means they can get Perez off the wage bill.
The 30-year-old is wanted by Alaves and a deal could be done for as little as £2 million.
Perez has been a flop at two Premier League clubs, after disappointing Arsenal fans following a£17 million move from Deportivo that only yielded one league goal.
Another who could leave West Ham this summer is Marko Arnautovic, especially if another big money offer from China comes to fruition.