'We've known about this for some time, but Steve has played on to help the team,' Dave Jones told the Echo.
'We decided he would have the operation after this match and he will now go in for surgery.
'Steve has helped us through the last five games when he had this problem, but he is now out for a minimum of three matches.
'We will try to sign a loan striker, but nobody will do us any favours, particularly clubs in the Championship.'
Kevin Campbell played the second half for City last night but we then start to struggle for cover. Luigi Glombard and Andrea Ferretti and the next options.
Campbell isn't the answer either. He's there to cover when Thompson comes off late in a game. Now into the latter part of his 30's Campbell should not be relied upon to play 90 mins.
Thompson seems set to miss a minimum of 3 games, possibly 5.