There will still be a "nagging doubt" about Ireland if they defeat Scotland next weekend, according to Eddie O'Sullivan.

Joe Schmidt's charges were dominated by England on Saturday and will now travel to Edinburgh in desperate need of a victory if they are to get their Guinness Six Nations title defence back on track.

But even if they get a win in Murrayfield, O'Sullivan suspects they will have more work to do to restore confidence for the remainder of the tournament.

"It's a tough one because if we were to lose next weekend, which is almost inconceivable, that would be a bit of a crisis," he said on RTÉ's Against The Head.

"We got caught there two years ago [in Edinburgh], there was bus gate and other things but the pressure's on and we have to win and we have to play well.

"Even if we win and we fall across the line, there'll still be that nagging doubt. I still think even if we do win, it doesn't answer all the questions. It changes momentum and it gets people thinking positively again, but you can't say everything is fixed.

"Wales could be the problem at the end of the season, they're still on track. On a day, France could nearly get it so it's a tough place to be because they've to go out and perform next week and they know even if they do, it doesn't solve everything."

Schmidt's decision to start Robbie Henshaw at full-back ahead of Rob Kearney was heavily criticised in the wake of that 20-32 loss to England, given that he had only played there once in his senior international career.

O'Sullivan believes that Kearney should be reinstated in the 15 jersey against Scotland but warned that he has a lack of game time under his belt since his recent return from injury.

"It was a big risk putting Robbie Henshaw full-back given the minuscule experience he had at international level [in that position]. It didn't work out and I think we have to acknowledge that," he said.

"I think Kearney should come in, but Kearney has played very little so he's no better off than he was a week ago."