Queens Park Rangers insist they still expect London Wasps to return to Loftus Road for next season. Wasps shared the ground with Rangers but moved to Wycombe in 2002, allowing Fulham to become QPR's tenants.
Wasps chairman Chris Wright announced on Tuesday that his club will stay at Wycombe's Causeway Stadium.
But with Fulham set to go back to Craven Cottage, QPR say Wasps are contracted to return to west London as part of a deal agreed two years ago.
QPR chief executive David Davies said: "We welcome the fact that a decision has been made. However, we are very disappointed that Wasps did not inform us directly, prior to making this announcement.
"Based on what we understand to be true, we look forward to welcoming London Wasps back to Loftus Road next year, as per the terms of their contract with QPR Holdings."
Wasps began groundsharing with QPR in 1996, when Wright bought both clubs and formed Loftus Road plc, which Wasps were separated from after the company and football club went into administration in 2001.
Wright stood down as Rangers chairman that year and later became the club's Life Vice-President when he gave up most of his shareholding.