NEIL LENNON admits he is a worried man as the transfer window prepares to open.

The Celtic boss is desperate to add more players to the squad he has been rebuilding for the past year.

But he is even more anxious that the club do not suffer another ram-raid of their key assets, as happened last summer when Victor Wanyama, Gary Hooper and Kelvin Wilson were all enticed south for a combined fee of more than £20million.

Lennon accepts it is part and parcel of the job nowadays to be ready to continually restructure.

And he acknowledges it is testimony to the quality of the team he has has produced to deliver a third title in a row to Parkhead. But he really does not want to hear that chief executive Peter Lawwell's phone has been ringing with offers for the current crop of stars.

And, as he prepared to try and switch off to enjoy a holiday with his family, Lennon revealed what is gnawing away at him.

"I am worried about losing some players," said the man who is about to enter his fifth summer transfer window since taking charge in 2010.

"What excites me, though, is, if we can keep this squad together and add one or two to it, we can have another pretty good go at it in Europe.

"But that's the big question: Can we hold onto the players?

"I have no doubt there will be interest in them."

World Cup-bound Fraser Forster and Emilio Izaguirre are two Bhoys expected to prompt enquiries over the next few months.

Mikael Lustig's successful return to fitness after his hip surgery will also place the Swede back on the wanted list, while James Forrest has already been linked with clubs in England.

And Virgil van Dijk is already appearing on the radar of several clubs who have noted how quickly and well he settled in at Celtic after his move from Groningen last summer.

Russian and English outfits lead the chase for him.

But while there are no definite offers arriving at Parkhead, Lennon is happy to plan for next season with the Dutchman at the heart of his defence.

However, the late departure of Kelvin Wilson back to Nottingham Forest for family reasons when the campaign was already underway is a warning to the Hoops boss that situations can change very quickly, and leave little time to find replacements.

Lennon is bracing himself for just such a scenario if significant offers do materialise and said: "It is up to me to try and talk them out of it (going), and I will do everything I can to achieve that and keep them here, as I have done with many other players.

"But it is not always the case I am going to be persuasive. I'm not that good, at times."