Keith Wood says Ireland have been "thin" in the centre positions since the retirements of Brian O'Driscoll and Gordon D'Arcy and believes structural changes should be made when it comes to development of players.

Keith was speaking to Off The Ball along with The Irish Times' rugby correspondent Gerry Thornley as the Irish team digest a World Cup exit to Argentina.

"We have viable alternatives for a huge amounts of players but in certain positions we're pretty thin. We've been thin at 12 and 13 for a while with O'Driscoll and D'Arcy retiring. We haven't had any pure natural centres come in. We've had players come in and be phenomenal. Robbie Henshaw was just fantastic against France. He really, really was. But these are guys that have been manufactured into being centres," said Keith.

On the question of long-term structural changes to Irish rugby, he also believes some level of change may be required.

"I do think there does need to be some change because if we continue doing the same thing and we're still not getting past quarter-finals, that's a sign of madness trying to do the same thing and expecting a different outcome," he said, although he also emphasised that methods up to now have led to recent success in the Six Nations.

Ger posed the question whether Ireland were fully prepared for a situation where Jonny Sexton was absent for a key game and Gerry discussed the provincial situation over the last two years in the case of Ian Madigan.

"Well, it's more on Leinster, really. He had an awful lack of rugby playing No 10 for Leinster in the two seasons that Jonny Sexton was a way which was very disappointing for him and for Ireland."