Wolves agreed a fee with Stoke for the winger, who was heading into the final year of his contract, after Kightly expressed the desire for a fresh challenge and to stay in the top flight.
“We would like to wish Michael all the best. He joined the Club as a raw young winger from non-league football and developed into an excellent player, making an important contribution to Wolves, particularly during our Championship winning season,” said CEO Jez Moxey.
“Michael wanted to remain in the Premier League, rather than sign the new deal, which had been offered to him and, therefore, we also faced losing him for nothing at the end of his contract.
“Given these facts, we agreed the deal with Stoke and we wish Michael well.”