Mark Wood admits he is battling "against the clock" if he is to win a spot in England's World Cup side.

Wood returns to the England side for the final ODI against Sri Lanka in Colombo on Tuesday but, having not played a game in the series to date, fears he may have fallen behind several others in the race for selection.

Now, with only one more ODI series to come (the five-match series in the Caribbean in February and March) before England pick their World Cup squad, he feels he is one of five men competing to complete the 15-man party.

"In my mind, there's one spot in the squad for five of us," Wood said. "Liam Plunkett is going to play: he's been our best bowler for a while. Chris Woakes has been so consistent. He is a great bowler and he is going to take the new ball. And Ben Stokes balances the team.

"So you've got one spot between me, Tom Curran, who feels he has got his slower ball back, Olly Stone, who bowls rockets and is ahead of me at the moment, Sam Curran, who can bat, and David Willey, who had a good summer. We're all probably vying for that one spot."

It's hard to disagree with Wood's assessment. With England's tactic of playing two spinners in most circumstances working well for them, and the management understandably keen to have some left-arm variation - provided by either Sam Curran or Willey - in their attack, it may well prove that Wood is now an outside bet for that final place.

With the World Cup having been a focal point of England's cricket for the last four years - and Wood having been a regular part of the ODI side in that period - it would heart-breaking to miss out at this stage. As a result he is hoping to improve his game in the final months before the tournament, both by lengthening his run-up in order to avoid some of the stress he puts on his body and by developing a new slower ball.

"It can be frustrating when you are just on the outside with a World Cup around the corner," he said. "I'd be lying if I said I didn't have one eye on that. I know that, if I don't do well here, I am one tour away from not making that World Cup squad. And that's something we've been building up to for over four years. Ever since the last one. So I've got to do the business."

"I've managed to swing the new ball out here so that has been a plus. And I have been trying to work on a few new slower balls. I feel I can get better with a few slower balls.

"But I'm against the clock a little bit. Everyone is fighting for that one spot so it is not like I can keep working on a slower ball for the next three years."

While such competition for place could disturb the equilibrium in the squad, Wood insists it will not be allowed to do so in this England camp. With Eoin Morgan having confirmed he would drop himself from the team if his form was not up to scratch - he may rest himself on Tuesday to provide opportunity elsewhere - the mood in the camp is, Wood says, selfless and positive.

"We're one team," he said. "We're all together. I want my friends to do well. I'm an England fan and I want England to win.

"You don't win nine series on the bounce [a statistic that excludes the one-off defeat against Scotland]. It's good to have healthy competition without being all bitter or sour. That doesn't help anyone. And I don't think Eoin Morgan would have you around if you weren't behind the team.

"Some of the net sessions have been pretty hairy as all the bowlers have been charging in trying to get a spot in the side. I've just got to prove myself and get better. And if I can do that, hopefully I should get my spot back."

Meanwhile Chris Jordan, who has recently arrived in Sri Lanka, trained with the squad on Tuesday. Jordan has been added to the squad with a view to playing in the one-off T20I match that follows the ODI series.

But while Jordan took part in the warm-up football, there was no sign at training of Jonny Bairstow. Bairstow's ankle injury remains a concern and it is doubtful that he will be fit to play in the first Test.

England may well call up Ben Foakes, the uncapped Surrey keeper, within the next day or two. Olly Stone and Joe Denly, who could make his first ODI appearance this decade on Tuesday, also sat out the football section of training.

George Dobell is a senior correspondent at ESPNcricinfo