IRELAND HEAD COACH Joe Schmidt admits the only sure way of knowing if a player will perform at international level is by seeing them at that grade.

The Kiwi has named three uncapped players in his 40-man Six Nations squad after handing out nine new caps during the November internationals.

Billy Stickland / INPHO Billy Stickland / INPHO / INPHO

Andrew Conway has played under Schmidt when both men were at Leinster, but for Rory and Niall Scannell it will be a first experience working closely with Schmidt.

The head coach has clearly been impressed enought to call up the Munster brothers, but when asked about them today opted to reserve judgement on whether they are ready for the international arena.

Injuries forced Schmidt to play Carbery at fullback against the Wallabies. James Crombie / INPHO James Crombie / INPHO / INPHO

“You never know that they’re ready,” Schmidt said at the Six Nations launch in London, before pointing to Joey Carbery as an example of how untested players can cope in tough circumstances.

“Joey Carbery had his 21st birthday in Chicago on the Tuesday (before facing the New Zealand). He’s got to go on and negotiate the last quarter with the All Blacks, that black wave coming back into the game and nearly washing over us like they had in 2013.

Ryan Byrne / INPHO Ryan Byrne / INPHO / INPHO

“Did he stand up? He negotiated his way through the game superbly. Throwing him on against Australia at fullback and he did an admirable job out of position.

There are some guys like Rory Scannell, who is playing more at 12, who may have to deputise at 10. Again, you’re not going to know. You get a sense at training, so over the next few days we’re going to get a better idea if we think guys are going to be able to slot in or not.”

While the younger Scannell brother is one of four centres competing for a place alongside Robbie Henshaw in Ireland’s midfield. Hooker Niall is automatically a step further up the depth chart as he competes with James Tracy to deputise captain Rory Best.

However,  the pressure will be on for whoever does get the nod to pull on an Ireland jersey this spring.

“Niall Scanell has done really well,” added Schmidt, “the two boys have been an integral part of Munster’s real revival this season.

“But it is difficult to know until they actually get into the Test arena. Unfortunately, you don’t get a second chance.

Niall Scannell draws a breath against Leicester. Dan Sheridan / INPHO Dan Sheridan / INPHO / INPHO

“You go out and if you’re behind the eight ball in that game, you’re playing catch up. We’ve got to try and make that assessment in the next few days, because your windows of preparation are very short as well.

“They’re two lads that I don’t know too well. Rory’s been in camp with us a few times. Niall would have been, but he had an elbow issue earlier in the season. At the same time, he’s come through really well.”

- Additional reporting by Murray Kinsella