Montgomerie - receiving treatment. (Getty Images)

Colin Montgomerie was continuing to have treatment on his three bruised fingers this weekend ahead of his planned flight to America for the USPGA championship.

Three weeks after finishing second to Tiger Woods in the Open, Montgomerie pulled out of the Johnnie Walker Championship at Gleneagles after hurting himself on what he called "one of the worst shots I've ever hit".

The 42-year-old Scot, who had needed to finish first or second to go top of the European Order of Merit for the first time since 1999, withdrew after 13 holes and flew back to London.

Guy Kinnings, Montgomerie's manager, said: "Colin had an X-ray first which established no bones were broken.

"He then went to see a specialist and initially it looked as though there might have been some serious ligament damage.

"He was very concerned then, but we had another specialist look at it and it now appears it's not so seriously damaged.

"But the fingers are still very sore and tender and there's bruising around the bone. Colin will see how it goes with the treatment the next day or day and will gently try it out."

Montgomerie is due to fly to New Jersey on Monday morning for the final major of the season, which begins at Baltusrol on Thursday.

He was one of three USPGA-bound players to scratch from Gleneagles.

David Howell, who has not played since injuring himself at the US Open in June, played in the eve-of-tournament pro-am, but decided his torn abdominal muscle needed more recovery time.

Then midway through his second round Stephen Gallacher quit because of the back trouble which has plagued his career.

The chances of them playing this coming week - or at least being fully fit - appear far slimmer than Montgomerie's.

It was a driver off the fairway that is thought to have caused the problem for the seven-time European number one.

He caught it heavy and with the ball squirting out right into heavy rough he was then forced to hack it out and the effort of that left him wringing his fingers.

Montgomerie played four more holes, but at five over par decided he was only aggravating the injury by continuing.

"It's still a bit inflamed, but with a couple of days' rest I should be OK," he said.

"The flight on Monday is my one fear, but I've been given some stretching exercises to do.

"I'll also probably play only nine holes on Tuesday and nine on Wednesday."