Westley says that Chelsea, Liverpool, Manchester City and Arsenal have all been trying to sign Oxford in recent times, but their efforts have proved fruitless.
The 16-year-old put pen to paper on Tuesday as he signed his first senior contract with the Hammers and Westley is excited to see him progress at the Boleyn Ground.
"With Reece... there was interest from Chelsea, Liverpool, Manchester City and Arsenal," he said. "Having seen him play for England, as captain across Europe, he is one of the best centre-backs in Europe. He's got a big future and we hope to see them both one day in the first team."
Oxford has already been capped up to under-17 level by England and is expected to progress through to the senior side.
A powerful and commanding presence, the youngster is also technically adept and he has impressed at youth-level for the Hammers.
Oxford has still not made his senior bow for the club, but if Westley is correct in his assessment that he is among the best young defenders in Europe, then his debut cannot be far away.
West Ham have expressed a desire to bring through more players from their famous academy system and Oxford's commitment, despite interest from high-profile clubs, is a signal of their intent.