Joe Schmidt has handed Ireland new boy Jean Kleyn a World Cup selection crib sheet.
South Africa-born Munster lock Kleyn made his Ireland debut just two days after qualifying on residency, when boss Schmidt's men saw off Italy 29-10 in Dublin on August 10.
The 25-year-old could find himself in a straight fight with Munster team-mate Tadhg Beirne for the final lock berth in Ireland's 31-man World Cup squad.
Kleyn has retained his place to face England at Twickenham on Saturday but has also been challenged to raise his level again, with the versatile Beirne taking a seat on the bench.
"We gave him some things to work on from last time and we want to see if those can materialise on Saturday," said Schmidt, of Kleyn.
"Because he's so new in, we felt that it was a priority to give him the time. Again, it is a fickle balance at the moment.
"Devin Toner knows our game inside out so needed less of the time, while Iain Henderson has just trained so well this week we're looking forward to seeing him out there."
Line-out titan Toner and his Leinster colleague James Ryan remain Ireland's premier lock pairing, with Ulster and British and Irish Lions star Henderson a combative and dependable option off the bench.
Munster's former Scarlets man Beirne and Henderson are both high-level back-row operators too, and that adaptability carries paramount importance amid the tight squeeze of a 31-man squad.
Schmidt remains intent on handing all his back-five scrum options chances to shine across these World Cup warm-up clashes however.
"It also gives Tadhg Beirne the opportunity to be that cover-all back-row, second row," said Schmidt.
"I'm not saying he's not good enough to start in either of those positions but he's nice security, having him covering all five of those back-five positions, albeit at seven we'd probably need to mix and match somebody but he can cover six, eight or five."
Ireland have rolled out the majority of their big guns to take on Eddie Jones' England in London on Saturday.
Johnny Sexton and Robbie Henshaw will sit it out, but head coach Schmidt insisted both men could have featured had they been required.
Ross Byrne will make his full Test debut at fly-half in the absence of both Sexton and Joey Carbery, whose World Cup remains in doubt due to ankle ligament trouble.
Captain Rory Best insisted Byrne has the perfect chance to prove his World Cup credentials, should he conjure a composed and confident showing against a potent England side this weekend.
"When you come to Twickenham you realise the magnitude of the stadium," said Best.
"I've been lucky enough to play here several times.
"It's a fantastic place to play rugby, it's a great place to play rugby – but it's also a great place to show what you're made of, and to show your value to this team. And that's Ross' opportunity.
"The thing for the rest of us now is to make sure that we step up to make it easier for him to step up.
"We're in a good place and looking forward to tomorrow.
"It's going to be hot for both teams, but they could be similar to the temperatures at the World Cup, so it's good practice.
"Both teams will be facing the same conditions; we play enough rugby in the wind and the rain that it's probably not right to moan about the sunshine!"