Hartley, 32, and 30-year-old Vennegoor of Hesselink have both been told to seek alternative employment following the expiry of their contracts.

The Dutchman may be quickly replaced up front by Nancy striker Fortune, who is mulling over offers from Celtic, Hull, Portsmouth and Fulham.

Mowbray hopes his personal relationship with the £3.8million-rated forward, who he took on loan to West Brom in January, will help sway him towards Parkhead.

And, although Mowbray admits Celtic cannot compete financially with clubs in England's top flight, the former Hoops player feels the club's pulling power may swing the deal their way.

"My advantage is I have worked with him - he knows me as a coach, I know his strengths and weaknesses," the Celtic manager told a media conference convened to promote the club's summer coaching courses.

"I don't think it's any secret that the English Premier League clubs get £30-35million each year off their television deals and the Scottish clubs don't.

"But what I do know is we have a huge pulling power from the support and the history and tradition of this club.

"Believe it or not, there's a lot of footballers who play for the love of the game as well as the money that goes with it.

"To play for a club fighting for championships, hoping to compete in the Champions League is a much bigger draw than taking the money sometimes and going and fighting against relegation and playing in a league when there are only really four teams who can ever compete to win that league."

The former Hibernian boss added: "As a manger I respect all footballers, especially one I have worked with and know what a good man he is.

"But he does have choices and that's because of his talent and ability.

"I think it will happen naturally over the next day or two. I'll either be sitting watching him shaking someone's hand and holding a shirt up somewhere at an English Premier League club, or you will all come back here in a few days' time and meet the guy yourself."

Hartley and Vennegoor of Hesselink will have to pursue their options after the end of their Celtic careers were confirmed.

Hartley has an offer from Iraklis Saloniki while he has been linked with Hearts, Ipswich and Sheffield United, while the Dutch striker has been linked with a return to his homeland or a move to Greece or Croatia.

"I had a good long conversation with Paul," Mowbray said. "The outcome of that is Paul won't be offered a new contract. He is free to look for other employment.

"I have had no contact with Jan. Jan is out of contract - he is free to seek other employment and I'm pretty sure that's what he will be doing at the moment."

Mowbray added: "I want to put my own stamp on it, bring some players in I that I want to bring and have attributes that I like in footballers."

There is some sense of urgency in Mowbray's quest given that Celtic begin their Champions League qualifying campaign on July 28/29.

"We would like to get one or two in before that," Mowbray admitted.

"We're working very, very hard. It's not always easy, especially when you're looking for good players with options.

"Hopefully we will make one or two signings the supporters get excited about.

"Hopefully they will be of the right standard to lift the quality and intensity on the training ground."

Mowbray, who is unsure whether Scott Brown and Stephen McManus will recover from injury in time to make the European kick-off, recognises the need to be imaginative in the transfer market though.

"You can find some very, very talented individuals that you can get cheaper," the former Middlesbrough captain said.

"We tried to do that at Hibernian and I like to think we proved that you can do that.

"The expectations sometimes of the bigger clubs is that they want ready-made footballers.

"My job I feel is to try to give them some ready-made footballers but also to build this squad and find some players that our supporters will never have heard of, and yet become big players. It's about getting the balance."