Ireland head coach Andy Farrell has warned his players nobody can afford to become complacent after selecting scrum-half Craig Casey ahead of Jamison Gibson-Park for Friday's Nations Championship clash with Argentina in Dublin.

Ireland head coach Andy Farrell has cautioned his squad against complacency after naming scrum-half Craig Casey ahead of Jamison Gibson-Park for Friday's Nations Championship clash with Argentina in Dublin.

Casey will line up alongside returning fly-half Sam Prendergast, with British and Irish Lion Gibson-Park relegated to the bench as Farrell looks to foster competition for places ahead of next year's Rugby World Cup in Australia.

Nick Timoney has also been handed a starting berth at openside flanker, while Sean Jansen takes the number eight shirt in the absence of injured skipper Caelan Doris.

"If ever a player feels comfortable, we're failing the group," said Farrell.

"We've not got those players anyway. I don't think people are comfortable, just by their nature, but if you want to keep ambition growing as a group then you've got to keep the ambition within the individual."

Casey, 27, made his Ireland debut back in 2021 but has accumulated the bulk of his Test caps coming off the bench as a replacement.

"Craig deserves to play in a big game at the start of the season, to have the responsibility to be in charge of the week and how they go about that and take responsibility for how we play on Friday," said Farrell.

"We need him to be able to have the opportunity to do that. Plus he's been playing pretty well himself.

"He knows the competition is there but he's got the shirt so it's up to him and his team-mates to make a good first impression."

Prop Andrew Porter, flanker Ryan Baird and wing Mack Hansen are all set to make their first international appearances in 12 months, having each been sidelined with injury.

Hansen, who is expected to start on the left wing, bagged a hat-trick in a 46-19 victory over his native Australia last November, but has been absent from the Ireland squad since their 24-13 defeat to South Africa the following week due to a foot problem.

"It's fantastic to have Mack back, first of all for himself, really," said Farrell.

"He's been through a lot, and it's great to have not just his ability as a player but to have his personality back in the group."

Ireland secured consecutive victories over Australia and Japan in the opening rounds of the Nations Championship before rounding off the summer series with a defeat to New Zealand.

Farrell has rung the changes with seven alterations to the starting XV that were beaten 40-21 by the All Blacks, with hooker Dan Sheehan stepping up to take the captaincy from Doris.

Following their home fixture against the Pumas at the Aviva Stadium, Ireland face Fiji on November 14 before taking on world champions South Africa seven days later.

"It's a year that means a lot to us, so it's an exciting one because we want to grow our game and make sure that we build the right belief for what's coming in 12 months' time," said Farrell.

"There's no better way to start that 12-month journey with a first game of the international season against a really tough and respected opponent in Argentina."