Neil Lennon suspects that Victor Wanyama has already played his last game for Celtic and has criticised the 21-year-old's agent for being "petty" and "economical with the truth".

Tellingly, neither Lennon nor any other senior Celtic figures have any problem with the way that Wanyama himself has handled talks over a possible £12m move to Southampton. But the club are angry at criticism aimed at them by Ivan Modia, his agent, who blamed them for trying to force through a Southampton deal, for not giving him a pay rise, and for supposedly denying him a move to Queens Park Rangers last summer.

Celtic privately believe Wanyama is not pushing to leave and would be happy to stay, but Lennon admitted that his own gut feeling was that the Kenyan international would be with another club soon. Liverpool, Cardiff City and Stoke City are all interested and previously he has been a target for Arsenal.

Selling him for £12m, having paid only £900,000 for him in 2011, would maintain Celtic's business model but Modia's provocative remarks have gone down badly within Parkhead. "There is a bit of mud-slinging going on, which we feel is unnecessary," said Lennon, echoing a statement released by the club 24 hours earlier. "We have done nothing wrong apart from accept a bid from a club for a player we value very highly. Now it is not up to us regarding a player's negotiations, personal terms or the agent's personal terms. We have done nothing wrong. The club made that clear and I would like to echo that.

"Everyone knows that we did offer him a contract extension and we did offer him a pay rise. But that was rejected. So I think they have been pretty economical with the truth. We feel we have done our business in the proper manner. It's a pity they have decided to come out and go public and have not really told the whole story.

"I don't even know if QPR made a bid last season. If they did, then it was nowhere near the valuation we have of Victor so it never materialised. We are well within our rights to do that. It's not like we are stopping the player from progressing his career. He is our player. One, we don't want him to go. Two, if he is going to go, the club has to match our valuation of the player. That's what Southampton have done. They have handled things very professionally. Personally, I think it [Southampton] would be a very good move for Victor in terms of his career going forward. There seem to be other parties wanting to block the deal.

"Our relationship with Victor is as good as ever. There has not been one day when he has said he is unhappy here. He is actually very happy. My own gut feeling is that a deal will get done somewhere along the line. But I'd like to emphasise the relationship between me and the player and the club and the player hasn't changed. It's been a bit petty and unnecessary the last couple of days."

Exposure in the Champions League had been essential to Wanyama being valued at £12m, said Lennon, and there were others at Parkhead who could also put themselves in the shop window. "We have others who will maybe not be as highly valued as Victor, but I do feel we have got a couple of nuggets in the squad who could eventually go for a lot of money. There are eight, nine or 10 players who can play at that Champions League level on a consistent basis. In terms of their price, playing in the Champions League drives it up, though it doesn't make them better players. We always believed they could play at that level anyway, but that gives them a stage to prove it."

Lennon said he was unaware of any official bid from Cardiff for Wanyama and nor had there been any fresh contact from Hull City about Gary Hooper despite reports of renewed interest and a £5m offer. Unless a deal is concluded to sell him, Wanyama is due to rejoin Celtic when they are at their pre-season training camp in Germany on July 4.

Celtic have already spent around £4.5m on striker Amido Balde and centre-back Virgil van Dijk this summer. "Amido is a very good header of the ball and attacks crosses very well," said Lennon. "He is a bit raw, which you expect at 21. We liked the look of a Portuguese player called Eder a few years ago and he has gone on to Braga and is valued highly – so we are hoping Amido will progress in a year or two's time and become a top class centre-forward.

"Virgil we feel is technically very good, has great presence on the pitch and will suit our style of play. Again, he is 6ft 4in and we have been looking for a dominant partner for Kelvin [Wilson]. We are hoping Virgil will be the answer."

Steven Mouyokolo, the 26-year-old French central defender who was at Parkhead at the end of last season, has returned on a trial and will be taken to Germany. But the club has not made a move for Monaco forward Ibrahima Toure.

Meanwhile Celtic await a decision on whether or not their Champions League second qualifying round tie with Cliftonville has been switched so that the first leg on July 16/17 is in Belfast, as both clubs would prefer.

* Lennon was speaking to promote a match in support of Stiliyan Petrov's Charity Foundation. The match, on Sunday, September 8, will involve Petrov himself, many of his former team-mates and other football and celebrity figures.