"If we can find one player who can help us like we need, with the quality and a different player for getting in our squad, we are going to do it".
"We can't sign with payment for one player", Emery said at a news conference on Thursday.
Juventus are reportedly close to agreeing a deal with Ramsey, who can leave for free in the summer when his contract expires or in January if a fee can be agreed, but Emery is pleased with the continued application of the 28-year-old.
Arsenal, however, are looking for a loan deal for the player and Emery has revealed that the Gunners can not afford to pay for any transfer fees and are looking for a loan deal.
"My idea and focus, I say to him every day, is that we need his performance for us", he said.
"After, his future belongs to him, his family and agent". We have taken more care in our training and pre-match planning.
Emery added: "We are working with the players who are with us now".
We head in to the game off the back of a routine 3-0 victory over Blackpool in the FA Cup last weekend which booked a date with Manchester United at the Emirates Stadium in the fourth round.
He has previously said Ozil lacks the physicality to compete in tough matches away from home and West Ham should provide tough opposition at their London Stadium home.
Nevertheless, Emery's sessions are notoriously intense and the Spaniard has conceded that he is toning down training to prevent burn out or repeat injuries.
Arsenal have been handed a major injury boost ahead of the game as Hector Bellerin is back from a calf injury while Nacho Monreal is also pushing for a recall after recovering from a niggling hamstring problem.