The 22-year-old Frenchman's future has been in doubt since the turn of the year, when he told Keegan shortly after his arrival as manager that he wanted to leave.

Quotes attributed to the former Le Havre player, who has family in London, this summer have suggested his feelings have not changed, with Arsenal and Tottenham said to be maintaining a watching brief.

However, having witnessed his efforts in the first fortnight of pre-season training and his contribution in the 4-1 friendly victory at Hartlepool on Saturday, Keegan is hoping to retain his services.

The manager said: "Charles' pre-season has been absolutely tremendous.

"That's a massive boost for me because I did not know quite how he would come back. But he has returned absolutely spot-on.

"He has worked very hard, and he's a very valuable player because he can play in two or three different positions.

"I haven't talked with him. I don't ask players if they want to stay. They have got contracts.

"His attitude tells me, 'Yes', but I don't ask them."

Keegan revealed after the game at Victoria Park that he hopes to make four more significant signings after landing Argentina winger Jonas Gutierrez and Liverpool midfielder Danny Guthrie to date, and could do without losing such a versatile player as N'Zogbia.

He started wide on the left at the weekend and moved to left-back after the break, and has also played in central midfield in the past.

However, with Guthrie's arrival, Keegan has at least added strength in the latter area with Turkey international Emre heading for Fenerbahce.

The 21-year-old was handed a debut as a half-time substitute at the weekend and within eight minutes had set up Damien Duff for the second of his three goals on the day and added another himself.

Guthrie said: "Coming to Newcastle just happened overnight for me.

"This is just the start of things - it's only a pre-season game and the season will only get better.

"It (the goal) took a little deflection, but sometimes you need that, and if you don't have a shot, you don't score.

"To get a goal, an assist and a win was a big bonus. The main thing was to get the rust off and get a feel of things again.

"The first week has been really tough. I have been finding out how things work up here.

"It's a really big club, but it's nice to finally play a game. It can only continue to get better for me."

Keegan's squad at Hartlepool was severely limited with Michael Owen, Steve Harper and Habib Beye missing with minor injuries, Mark Viduka and Andy Carroll recovering from longer-standing problems and Jonas still awaiting his registration.

In addition, Joey Barton is yet to be released from prison, where he is serving a six-month sentence for assault and affray.

However, there has been more encouraging news of Viduka, whose long-standing Achilles injury is on the mend.

The 32-year-old had an injection at the end of last season amid fears he could be sidelined for a more significant period.

But he is now expected to resume training within weeks, and hopefully for Keegan, before the new season gets under way.