Neil Lennon intends to have talks with the agent of Victor Wanyama to find out how long the player is content to stay at Celtic on his current terms.

The club attempted to sign the 21-year-old on an improved deal in October but Wanyama rejected the terms and, at the time, his representative Rob Moore said that the offer "fell short of his expectations". The matter has been put on hold since then, partly because Wanyama remains under contract until 2015.

Trying to retain the Kenyan midfielder is one of Lennon's key objectives this summer. Wanyama said on Wednesday that he wanted to stay at Celtic next season, although that position could quickly change if Arsenal, or another leading Barclays Premier League or continental side, were to follow up reported interest.

Normally Celtic would be under pressure to sell now. The club's admirable business model relies on identifying and signing young, emerging talent at an affordable price, getting two or three seasons' play out of them, then selling at considerable profit, which is then reinvested. Wanyama is at the end of that cycle. What alters the picture at this year is Celtic's income, around £25m from reaching the last 16 of the Champions League. That might empower chief executive Peter Lawwell to offer Wanyama an improved deal to stay.

"I've had conversations with Rob," said Lennon. "I've got a great relationship with him. The last conversation we had was basically him asking me if Victor was going to get time off between now and the end of the season. When it comes to money and other aspects of contracts, that's between Rob, Peter and Victor. It's for them to sort out. But Rob is aware of my position on Victor. There is no big rush in Rob's eyes for Victor to leave. But the reality is that if a big offer comes in he will have to do his job for his client. I understand that. He's been pretty up front and fair with us so far. If the kid wants to stay, then that gives us half a chance.

"We need to speak to his agent and see what it will take for him to stay. Once we get that sort of figure or figures then we can get to thrashing out a contract. He's never intimated that he wants to leave, he's never intimated to me that he doesn't like it here. He's really low maintenance and has been happy this year.

"We'd love him to stay and it would give the squad a real shot in the arm. You look at his performances here and against Barcelona he was magnificent. A colossus. He has been all year, technically brilliant, fantastic strength, super in the air, and he can play. He would walk into a lot of Premiership teams.

"He has experienced the Champions League and that competition can be a carrot for him at Celtic, but the problem we have here is that, realistically, are they going to play more than six games. They weight that up with what is going on over the border. That's always the dilemma that we are in."

Wanyama, Gary Hooper and Fraser Forster are where Aiden McGeady and Ki Sung-Yueng were in 2010 and 2012 respectively, ie ripe for sale. The income from the club's European run means that is not currently necessary, explained Lennon. "We don't need to sell because of the Champions League money, unless I'm speaking out of turn. We sold McGeady and Ki in the past. If the offer is right and we feel it best for the club, then we will do it."

Lawwell said earlier this week that Celtic would pay a transfer fee of up to £5m for a player, but only for a player who could be subsequently sold on for more. "It depends on the player, if he is going to make us better, if we feel there is a resale value in him, if he is going to bring us success.

"But I won't break the wage structure here. Regardless of the transfer fee, wages will be important in any negotiations. I don't want to break the spirit in the group. If you do that, you will have your door knocked on every other day. We have to be very mindful of that. But if there is a £5m player out there who can make us better and who is within the wage structure, then we would do it."

Lennon was asked whether Celtic could take heart from Borussia Dortmund's progress through the Champions League this season, given that they operate on a more modest financial level than any of the other three clubs in this week's semi-finals. Lennon's admiration for them was accompanied by recognition of the advantages that they still enjoy.

"They are a great example to a lot of clubs, but they do get 80,000 fans every week and I don't know how much they make from TV and what they get for winning the championship in Germany. I think the comparisons with us are a bit false. We wouldn't be anywhere near Dortmund's market. They have just sold Mario Goetze to Bayern for £30m. I wouldn't say it's a fair comparison with us, but the premise is the same."

Celtic's crowds are roughly half those of Dortmund's but Lennon insisted that was still an impressive figure, and he praised the club's initiative in which £100 will be given back to every fan who buys an adult season ticket. "A lot has been made of our crowds this season but we are still averaging around 40,000 which is pretty healthy compared to a lot of other clubs. We are very grateful for the support.

"The Champions League was pretty special. We more or less had full houses for every one of those games. Because it's the Champions League, everyone wants to see it, which is fine. The crowds for SPL games are a bit down but not dramatically. This is a gesture to bring them back a bit more and give them something back. There is a feeling that we do overprice the game in Scotland. I think it is a brilliant gesture by the club and a real incentive for supporters."