The 28-year-old England international was missing from the side which secured a creditable 1-1 draw at Manchester United in Sunday's Barclays Premier League opener after a summer disrupted by a bout of mumps and a calf problem.

With Mark Viduka also sidelined as he recovers from an Achilles injury, Keegan was short of options at Old Trafford and therefore delighted by Obafemi Martins' return to action.

Martins headed the Magpies into the lead at United, and he looks likely to lead the line once again when Bolton Wanderers visit St James' Park on Saturday with Owen and Viduka set to sit out once again.

Keegan admits he could probably send the former Liverpool and Real Madrid frontman out against Gary Megson's side if he needed to, but is acutely aware of the possible consequences.

He said: "Michael probably won't be (fit), and Mark Viduka certainly won't be.

"I probably could rush Michael back and then knock him back five or six weeks.

"We are probably strong enough to do without the two of them - but when they come back, it will give us a massive boost."

That is perhaps a measure of the growing optimism in the wake of Sunday's performance, in which new signings Jonas Gutierrez, Fabricio Coloccini and Danny Guthrie made excellent league debuts.

Owen could make the Carling Cup trip to Coventry City next Tuesday evening, but is more likely to return for another tough Barclays Premier League assignment at Arsenal the following Saturday.

Viduka has returned to training, but is still some way off figuring, while defender Steven Taylor is expected to shake off the ankle injury he picked up at the weekend after withdrawing from the England Under-21s squad for last night's friendly victory over Slovenia in Hull.