Iain Henderson has said that it is "so hard" to predict who will be involved in Ireland's Rugby World Cup warm-up against Wales next weekend.
The Six Nations champions will face Warren Gatland's side on August 8 at the Millennium Stadium, before hosting the side at the end of the month.
The lock told BBC Sport: "Joe [Schmidt] is so hard to predict when it comes to selecting squads. He keeps us on our toes at all times, so it's typical of him to be keeping us in the dark.
"It's making everyone work harder and harder all the time, and that in turn probably puts more pressure on him just to make those selection decisions.
"We're not even sure what the squad will be like for next weekend's game yet, Joe has kept us in the dark on that and no doubt that's deliberate."
Ireland also play Scotland and England ahead of the World Cup, which gets underway in September.
