Sullivan believes he can convince Lukaku to remain in the capital and play at Upton Park alongside Andy Carroll, who could be about to secure a permanent £15million switch from Liverpool.
Sullivan told the Daily Mirror: "Lukaku would be a loan again. We'd maybe buy him a year later if Chelsea decide they don't want him.
"If we sign Andy, it would be a record signing for the club. He and Romelu would be devastating. The best strike-force outside of the top six or seven.
"Lukaku has been amazing for West Brom this season and I'd hope that he would prefer to live in London."