England striker Michael Owen is to undergo a second scan on his injured groin after limping off the field for the second time in a week.
In a development which will set the alarm bells ringing for national boss Steve McClaren, the 27-year-old striker asked to come off six minutes into the second half in Newcastle's 3-1 Barclays Premier League victory over West Ham.
Owen, who was also substituted at Derby on Monday evening to spark speculation that he needs surgery to repair the injury, will see a specialist tomorrow as the Magpies try to get to the bottom of a problem which could also have major implications for England ahead of next month's Euro 2008 qualifiers against Estonia and Russia.
Newcastle boss Sam Allardyce, who ruled the striker out of Tuesday night's Carling Cup clash with Arsenal, said: 'We will know better tomorrow. It is still a groin problem which we will have to look into a little deeper because it has become persistent.
'We will make a decision from there. We will probably scan it again, have another specialist opinion and then see where we go from there. But he is definitely out for Tuesday.
'I am worried that he asked to come off today because he felt it, whereas it was me who took him off against Derby, so since then, even though the scan was clear, there's a persistent area which is causing him a problem.
'We need to look deeper into that.'
If surgery is required, Allardyce insisted that the club would waste no time.
Asked when any operation would be done, he said: 'Straight away, if that's the case. We will look after Michael Owen's interests more than anybody else's.
'He is our most expensive asset, so we must not go on any longer than we need to, we must address the injury straight away.'
Owen's continuing fitness problems and the loss of defender Claudio Cacapa to a similar injury took the edge off a good afternoon for Allardyce, who saw his side run out relatively comfortable victors after finally wearing down the Hammers.
Mark Viduka headed the Magpies in front with just two minutes gone and then after Dean Ashton had levelled on 32 minutes, restored his side's lead four minutes before the break.
The impressive Charles N'Zogbia wrapped up the win on 76 minutes, and Owen's replacement Obafemi Martins passed up a glorious opportunity to make it 4-1 at the death after rounding keeper Robert Green.
Allardyce said: 'I am very contented. It was a very satisfying result today and in many cases, very satisfying in terms of the performance.
'But there is still a lot to work on and a lot to get better at.'
Hammers boss Alan Curbishley admitted his side's defending had cost them on an afternoon when Ashton, particularly in the wake of Owen's problems, pushed himself closer to the international reckoning.
Curbishley, however, insisted the striker still has a long way to go before he is back to full fitness after more than a year out with a fractured ankle.
He said: 'He needs some more football, he needs as much as he can get.
'If you had seen Dean three weeks ago at Reading and last week against Middlesbrough and now today, he is slowly getting stronger and stronger.'
Asked what he would tell McClaren if he inquired about Ashton, Curbishley said: 'I would just say to him he has been out a year and a bit.
'Steve McClaren has been to our games and he has seen Dean.
'They have been watching all the games and they will have seen Dean has slowly got stronger and sharper.
'We will have to see. Two weeks is a long time. Anything can happen.'