Montgomerie was a top-10 player only two years ago

Montgomerie, who is separating from his wife, did not appear for the event's pro-am, nor did he attend the European Tour's annual dinner.

The Scot cannot finish lower than fifth at Wentworth this week if he is win a spot in next month's US Open.

He is 56th in the world rankings after finshing 128th at the TPC of Europe.

That was his worst tour result since his debut in 1987.

Only a top-five finish at the Volvo PGA Championship would take him back to the top 50 and earn him a US Open invite.

The 40-year-old has played in 49 straight majors, but has missed the cut in five of the last six.

Montgomerie, who says he and his wife Eimear may get divorced, was 20 shots off the lead when he missed the cut at St Leon-Rot last Friday, and looked a shadow of the player who ruled Europe for seven years in a row.

It's going to take a little while, but time will hopefully heal some wounds and (Montgomerie) will be able to go on and cope with it Bernhard Langer

Montgomerie is also currently not exempt for the Open at his home club Troon in July and unless he wins this week he will also have to decide whether to play in the qualifying event at Sunningdale on 28 June.

Speaking on Friday after his TPC display, Montgomerie said: "I enjoy my job, but I don't enjoy playing this way. I've just got to try again next week."

And there were words of encouragement for him on Tuesday from Ryder Cup captain Bernhard Langer.

"I spoke to him a week or 10 days ago and I'm very positive about his goals and where he's heading," said Langer.

"I think he'll come out of this. It's going to take a little while, but time will hopefully heal some wounds and he'll be able to go on and cope with it."