The much-scrutinised practice of selection in sport boils down one essential equation: known quantities against potential– proven performers against untried talents.

In the coming months as the Rugby World Cup encroaches to within touching distance, international coaches will try to strike this balance. And the stakes are astronomically high.

With a multitude of worthy names vying for five slots in a 31-man squad, the conundrum awaiting England boss Stuart Lancaster with regard to his back-row blend is a painstakingly tough one.

An initial party of around 50 will be announced on Wednesday. Expect intense debate. Skipper Chris Robshaw, James Haskell, Tom Wood, Billy Vunipola and Ben Morgan – fitness permitting – are in pole position having won caps throughout Lancaster’s three-and-a-half-year tenure. However, a certain Exeter Chief cannot have done more this season to disrupt the status quo.

Rob Baxter’s side missed out on the Aviva Premiership play-offs on points difference at the end of a thrilling final afternoon. Still, they boasted one of the most influential performers in the division.

Since September, Dave Ewers has shown himself well worthy of a shot at the Test arena. Here is a look at how the blindside flanker could make England a better side.

Attack

When Lancaster’s team have lost over the past season, their phase-play in midfield has let them down, becoming stagnant and predictable in the middle third of the field.

This was most noticeable against South Africa and New Zealand this autumn, but the below passage from a 19-9 defeat to Ireland is emblematic of the same thing:

Luther Burrell‘s outside arc has turned the hosts and a further foray from Robshaw gets over the advantage-line. Then though, momentum ebbs away. We isolate proceedings as George Ford shapes to distribute:

Vunipola was England’s top-carrying forward in this game, bringing the ball into contact 14 times. Rosbhaw, second on the list among the pack, only trucked up on six occasions.

Ireland could therefore take an educated guess as to the recipient of Ford’s pass, and were rewarded handsomely. First, Robbie Henshaw makes an excellent tackle to win the collision…

…before Best latches onto the ball…

…and comes away with it in a turnover referee that Craig Joubert is happy with:

With Ewers in the line-up alongside Vunipola, another powerful runner would be added to share the load, inciting defensive indecision from the outset.

This carry came 80 minutes into the recent clash with Wasps:

Alapati Leiua is a mightily strong man. However, he goes too high and Ewers punishes him with overwhelming leg-drive:

The most effective way to quell such a specimen is through rapid, focussed line-speed. Saracens tried to impart this technique a fortnight ago. Unfortunately for them, Ewers and Exeter were ready.

Watch what happens when Jamie George shoots up out of the defensive line:

A swift pass to Thomas Waldrom shifts the point of contact and capitalises on the dog-leg created between George and Petrus du Plessis:

It is a lovely piece of skill, and brings to mind the thought of Ewers combining with Tom Youngs or either Vunipola, unbalancing the defence to send them rampaging on.

For good measure, to underline his awareness and industry, the Zimbabwe-born behemoth follows up to attend the ensuing ruck:

With Sam Warburton and David Pocock likely to be lurking in a beastly Pool A,  ball retention and vigilance at the breakdown will be vital.

Finally, to a spark of magic in the Challenge Cup quarter-final triumph over Newcastle Falcons:

Lancaster would categorise this as a ‘something from nothing’ moment. Certainly, the vision to spot blindside defence’s sluggishness in getting off the line…

…and the pace to exploit it before the execution of a superb out-the-back flick to Waldrom…

…is pretty special.

Defence

In the same way that his primary function is to pierce the gain-line on attack, one of Ewers’ key defensive responsibilities is to prevent the opposition gathering impetus in phase-play.

In this month’s superb win at Allianz Park, he was crucial in this aspect. While he only made seven tackles across the 80 minutes – significantly fewer than his customary tally somewhere in the mid- to late-teens – Ewers patrolled matters well and picked his moments.

Here, Saracens recover their own restart. Richard Wigglesworth is given quick ball and Mako Vunipola marauds forward. Ewers is equal to the task:

Starting in the body guard position, Ewers is out of the traps quickly – one of Andy Farrell‘s primary defensive principles:

Though the prop’s footwork prevents a straight-on hit, Ewers still manages to fell Vunipola behind the gain-line too:

Saracens opted to kick off the next phase. That cannot happen a great deal following a Vunipola carry.

Exeter needed heroic work-rate in the second period as wave after wave of Saracens runners battered their line. From this set-piece, the Chiefs were stretched off the back of an effective, intricate lineout move. Even so, the danger was snuffed out:

Once more, Ewers’ intervention is multi-faceted. Scooping up the loose ball before aiming a massive fend at Wigglesworth is more eye-catching, but a scrag-tackle on the scrum-half just as he looks to put through David Strettle is crucial:

Such subtleties are where back-rowers earn their keep, which brings us onto the defensive breakdown – another area in which England were comprehensively bettered by Ireland in Dublin.

Again, Allianz Park is the scene. Again, Saracens are in the ascendancy:

As Leicester Tigers showed during their victory over Wasps a week back, the breakdown is not simply about snatching Hollywood turnovers. Slowing down opposition ruck-speed can be just as vital.

In this case, Ewers must fight to get to the ruck in the first place. George Kruis has cleaned him out far beyond the previous breakdown (another Tigers tactic), so he makes referee JP Doyle of the situation:

Eager not to concede a penalty, Kruis lets go. Ewers is free to compete for the ball after Mako Vunipola is felled from the next phase. Notice that it takes four Saracens to budge him:

Naturally, Saracens are down on numbers for the rest of their attack, all because Ewers has made a nuisance of himself.

England are at their best when they have their most effective breakdown operators on the field together. Remember the 2014 Six Nations, when both Joe Launchbury and Dan Cole were helping out the back row?

Ewers would enhance those efforts, as this coup against Harlequins demonstrates. Full-back Ollie Lindsay-Hague attempts to counter before getting caught:

Even with Luke Wallace in close attendance, Ewers cannot be prised off the ball thanks to his bulk and copybook body position:

Referee Matt Carley has a straightforward decision and Henry Slade banged over three points.

Ewers is a lineout option for Exeter, though he is very rarely used. This will be one consideration for Lancaster, especially considering Wood has been a key cog of the England set-piece over a 36-cap career.

That said, Graham Rowntree has a wonderful track record of readying promising youngsters for Test level. The vast majority of England forwards that have been blooded in recent years – Launchbury, Kruis, Tom Youngs, both Vunipolas – have stepped up and excelled.

In fact, three of two of those men are British and Irish Lions, with two more almost certain of involvement in 2017. Ewers has that sort of elite potential.

He made the leap to Saxons level easily, and was a stand-out as Irish Wolfhounds were ousted in Cork this January. His versatility and aptitude at No 8 mean he would be a great option for the bench or one of the pool matches to ease the burden on Vunipola or Morgan.

In two months and three warm-up games before the main event, England could harness Ewers’ considerable ability into something truly terrifying.

Thanks to BT Sport and Premiership Rugby for the match footage. You can purchase tickets to the Aviva Premiership final at Twickenham here.