Tokyo - Ireland's injury worries continued to mount on Tuesday, five days out from their Rugby World Cup opener against Scotland, with a cloud over fullback Rob Kearney.

The 92-Test veteran's calf strain, picked up in training, is the latest in a series of problems for coach Joe Schmidt.

With Ireland now the world's number one-ranked side, Schmidt is keen to make a statement by fielding his top side in their tournament opener in Yokohama on Sunday.

But the question mark over the 33-year-old Kearney follows the hamstring injury that has already ruled centre Robbie Henshaw out of the first round Pool A fixture.

Winger Keith Earls has also been struggling with a knee problem.

A team spokesperson said Kearney was receiving ice treatment and his recovery was being closely monitored with no training scheduled for Tuesday or Thursday.

"There was a flurry last night about Rob Kearney, he's got a bit of tightness in his calf," the spokesman said.

"The plan is hopefully he will do a bit of running tomorrow (Wednesday) and it will ease up. If not Wednesday he'll have a run Friday. It just depends."

The outlook for Earls taking the field in Yokohama was brighter with the Munster flyer able to resume running this week.

If Kearney is ruled out, the Leinster fullback Jordan Larmour would be the likely replacement, while Joey Carbery, who is also returning from injury, has previously worn the 15 jersey.