Concern flared Tuesday about a nagging right foot blister that forced Masters winner Rory McIlroy to halt a practice round for the PGA Championship after only three holes at Aronimink.

The world number two from Northern Ireland said Sunday after limping through the final round of a PGA Tour event at Quail Hollow that he had a blister under his right little toenail that began hurting Friday.

He insisted it would not be a problem this week, but on Tuesday McIlroy checked his right shoe several times before taking off his right shoe and sock on the fourth tee and was later taken in a cart back to the clubhouse, ending his first practice round of the week.

The situation added drama ahead of Wednesday’s final practice day and Thursday’s opening round, with McIlroy scheduled to tee off at 8.40am local time alongside Spain’s Jon Rahm and American Jordan Spieth.

Top-ranked defending champion Scottie Scheffler and McIlroy, coming off his sixth major win last month and second Masters victory in a row, are favoured in this week’s major showdown over the 7,394-yard, par-70 suburban Philadelphia layout.

Before his late-afternoon setback, McIlroy was talking about how to approach Aronimink, known for difficult greens and wide landing areas for long drivers.