An optimist, they say, views the glass as half full. A pessimist, they say, views it as half empty. And a regular supporter of England at World Cups expects the glass to explode at any moment, killing all present with fragments of glass. It is an expectation conditioned by years of grim experience.

So there wasn't a great sense of surprise when news of Eoin Morgan's injury began to filter around the Ageas Bowl (or the Hampshire Bowl as the ICC, always mindful not to allow 'ambush marketing' would have us call it; they've spent the last few days putting masking tape over any tradename or logo across all World Cup venues). It was more a sense of 'here we go again, then'.

And then the relief. News a few hours later that Morgan had sustained "a small flake fracture" provided hope that he might - should, even - be fit for England opening World Cup match. Suddenly that glass was looking half full again.

In some ways, England are quite well covered should Morgan suffer injury. The team, generally, know their roles inside-out, Jos Buttler has shown himself to be an astute captain and James Vince looks in decent form with the bat. Morgan's withdrawal wouldn't necessarily prove a fatal blow.

But so important is Morgan to this team - so talismanic his presence, so unblinkingly positive his leadership and such good form is he in with the bat (he is averaging 94.50 at a strike-rate of 105.73 in his last 16 ODIs) - that his absence would surely weaken this side that has been created, in many ways, in his image. Nobody has played more ODIs for England (the opening match of the tournament should be his 200th) or scored more runs. He is probably as close to irreplaceable as anyone in the squad.

While the England management insist Morgan will make a "full recovery" and be available for their opening match, against South Africa at the Kia Oval (it's hard to resist teasing the ICC just a little) on May 30, there must be some doubt as to his fragility. While he should be fine while batting - protective equipment is excellent these days - there may be more concern about how he would fare in the field if he sustained another blow to the same area. He generally fields in the ring so is likely to encounter plenty of balls hit with great power.

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Did the use of the words "small" and "flake" in the ECB media release suggest they were protesting a little too much? Maybe only to those of us who have watched England in recent World Cups - and not so recent, really - and seen them beaten like a snare drum. But this is a different England and maybe we shouldn't allow bad memories to dim our enthusiasm.

England would have been put in a tricky position had the x-ray showed a full break. While that might have put Morgan out of action for anywhere between three and five weeks, they would have been loath to call a new player into the squad. Under tournament regulations, a replaced player cannot subsequently be recalled and England might well have been prepared to carry Morgan for the first half-dozen or so group games in the hope he could make an impact in the final half of the event. There will be great relief in the camp that they have not been forced into such a dilemma.

Morgan is not the only injury concern. Adil Rashid also misses Saturday's match with a view to managing his long-standing shoulder problem. He is not thought to be in doubt for the South Africa game, though it does provide a reminder of how many of these players are going to have to be nursed through the tournament. It is hard to imagine Mark Wood or Chris Woakes playing every game, either. Perhaps partly for that reason, England will utilise 12 players on Saturday to ensure the bowlers' workload is limited. These warm-up games do not carry List A or ODI status and can involve up to 15 players a side.

Rashid's absence provides an early opportunity for Liam Dawson to slip back into England duty. It is not ideal that Dawson has not featured in the England side this year but he has, at least, been in excellent form for Hampshire. He has played for England in all formats and is, by all accounts, a down-to-earth character. Indeed, in his press conference on Friday, he reacted to questions about his late call-up with all the apparent enthusiasm of a man taking delivery of a new filter for his Hoover-unbranded vacuum cleaner. For journalists hungry for a soundbite it wasn't ideal, but such an equable temperament may prove invaluable for England over the next few frenetic weeks.

It remains a shame that Dawson - and his Hampshire colleague, Vince - should be forced to miss Saturday's Royal London Cup final against Somerset at Lord's. The domestic Lord's final used to be one of the showcase events of the season; now it is not - arguably, anyway - even the biggest match of the day. Both games will be broadcast by Sky with the England game available on Sky Mix, which means it is free-to-air for some customers.

How such a clash of events has been allowed to happen remains unclear. The cynical might suggest the ECB are looking to undermine and overshadow their own 50-over competition ahead of its downgrading next year. The cynical are often right.