You can understand why the selectors are so keen on Joe Denly. In theory, he fills several holes in their World Cup squad. He is the reserve spinner, reserve top-order batsman, reserve middle-order batsman and a fine substitute fielder in a variety of positions. He is, no doubt, an admirably versatile cricketer. While England's final 15 will not be confirmed for a couple of weeks, word from the management suggests he is almost certain to be included; a remarkable situation for a man who has played one ODI this decade.

But, as his first two deliveries in Cardiff - both long-hops - were deposited deep into the stand at midwicket, it was hard not to wonder if there might have been some wishful thinking in England's appraisal of his skills. While he recently gained an unwanted record - he suffered a first-ball duck on debut in the IPL to complement the first-ball duck he suffered on first-class debut in 2004 - he can certainly bat and may yet come in at No. 3 in the Ashes. But expecting him to carry the role of a frontline bowler at the World Cup appears a high-risk strategy.

There is no intention to field him in such a role, of course. Denly is in the squad, in part at least, as a spin-bowling cover so will almost certainly only play if either Adil Rashid or Moeen Ali are injured. He is not the first-choice reserve batsman - that is likely to be James Vince - and there is very little chance of England fielding three spinners.

But if either Moeen or Adil do suffer an injury, England may well have to rely on Denly's legspin. And, at least of this evidence, that would be an uncomfortable position in which to find themselves.

Perhaps it's harsh to judge Denly on such a small sample size. These were just two balls, after all. He finished the over well enough and has certainly developed, in T20 cricket at least, as a useful option over the last few season.

But the sample size on which his bowling has been judged positively is pretty small, too. He has claimed just 47 List A wickets in his 15-year career and 25 of those have been taken overseas. Only once in an English season has he claimed more than four wickets. It might also be remembered that his maiden ODI wicket - taken against Ireland on Friday - came from a leg-side wide. Not only that, but Ben Foakes' stumping was so opportunistically delayed, the opposition skipper suggested it should have been a dead ball.

So his selection as a spin-bowling all-rounder is based disproportionately on the 2018 summer when he claimed 14 List A wickets. Encouragingly, four of those came in a high-pressure situation - in the Royal London Cup final - and against a good side in Hampshire. But less encouragingly, another four of them came against a weak Glamorgan side who lost seven of the eight matches they played.

He enjoyed a decent T20 campaign with the ball in 2018, too. But the role of spinner in that format - essentially much more negative that the wicket-taking approach shown by Rashid, in particular - would require some significant adaptation in the longer format. The worry is, with batsmen given time size him up, he would struggle to get through anywhere near 10 overs without the pace of Moeen or the variation of Rashid.

Part of England's reasoning around Denly's inclusion centres on the replacement rules at the World Cup. While injured players can be replaced at any time, they cannot subsequently be brought back into the squad. So England are keen to have a ready-made spin-bowling replacement in their 15 who could come in for a match or two as required without weakening the batting or fielding. If everyone is fit, there is no realistic scenario in which Denly plays.

On the surface, that makes some sense. Some of the contenders for the third-spinner role - the likes of Lancashire's Matt Parkinson - would have to be considered specialist bowlers, so having them in the squad would cover fewer holes.

But it also ignores the success of Liam Dawson in county cricket. Dawson has claimed 17 wickets in this year's Royal London Cup - only three men have claimed more - and is conceding just 4.01 runs an over. No one who has delivered 40 overs or more has been more frugal. The fact that he is also averaging 49.20 with the bat - underlines the sense that he can count himself unfortunate.

It ignores the depth added by Joe Root, too. Only last June, Root bowled 10 overs for the cost of just 44 against Australia in Durham. And while England would be nervous about going into an ODI with Root as one of a five-man attack, his presence as a sixth option is useful. He might well prove no more expensive than Denly.

We may well be on the brink of finding out how Denly would fare as a frontline bowler. There is some concern in the England squad about the fitness of Moeen for Wednesday's opening ODI against Pakistan at The Oval. While the rib injury is not thought to be a long-term problem, it is highly unlikely England will risk anyone this close to the World Cup. Denly may be given an opportunity to see what he can do. While his selection currently looks all but certain, prolonged exposure in such a role may not do his chances any good.

George Dobell is a senior correspondent at ESPNcricinfo