He has been replaced in the three-man team at St Andrews by Ryder Cup vice-captain Sam Torrance.

The 46-year-old partners Gary Orr and Paul Lawrie in the prestigious international event.

Montgomerie, Europe's number one and captain of the fourth-seeded Scots, had to pull out of Wednesday's pro-am after only five holes because of problems following root canal treatment.

Despite taking medication, he felt unable to face Paraguayan Raul Fretes in Thursday's opening group matches.

Ryder Cup team-mate Andrew Coltart had been the first man contacted to act as standby - but at such short notice he felt unable to leave his wife Emma and month-old baby daughter Bonnie at home in Surrey.

Instead Torrance, who partnered Montgomerie and Coltart to Scotland's only victory in the event in 1995, agreed to step in.

Ryder reunion

Montgomerie's withdrawal was a huge blow to the hopes of the host country, who if they win their round-robin group could face top seeds USA in Sunday morning's semi-finals.

Paul Lawrie: Under greater pressure following Montgomerie's decision to pull out

The inclusion of Torrance raises the possibility of him facing Tom Lehman, the man whose behaviour on the final day at Brookline he called "disgusting".

Lehman, who is joined by victorious Ryder Cup team-mates Mark O'Meara and Payne Stewart, was accused of playing a central role in the premature US celebrations on the 17th hole in Boston - a charge he denies.

Montgomerie will now be aiming to recover full health for next week's Cisco World Match Play championship.

He is expected to be one of the four seeds at Wentworth given a bye into the quarter-finals along with defending champion O'Meara, Lawrie and Masters champion Jose Maria Olazabal.

Draw for the group stages of the Alfred Dunhill Cup at St Andrews
Seeded positions in brackets:

Group 1: United States (1), Sweden (8), New Zealand, Italy.
Group 2: Scotland (4), Australia (5), Paraguay, Japan.
Group 3: South Africa (3), England (6), China, India.
Group 4: Spain (2), Ireland (7), France, Zimbabwe.

Winners of each round-robin group progress to semi-finals on Sunday morning. Final takes place on Sunday afternoon.

Dunhill Cup line-ups:

Australia: Stuart Appleby, Peter O'Malley, Craig Parry.

China: Cheng Jun, Wu Xiang-Bing, Zhang Lian-Wei.

England: David Howell, Mark James, Lee Westwood.

France: Marc Farry, Jean Francois Remesy, Jean Van de Velde.

India: Vijay Kumar, Jyoli Randhawa, Jeev Milkha Singh.

Ireland: Darren Clarke, Padraig Harrington, Paul McGinley.

Italy: Emanuele Canonica, Costantino Rocca, Massimo Scarpa.

USA: Mark O'Meara, Payne Stewart, Tom Lehman

Japan: Isao Aoki, Tsuyoshi Yoneyama, Katsuyoshi Tormori.

New Zealand: Frank Nobilo, Phil Tataurangi, Greg Turner.

Paraguay: Angel Franco, Carlos Franco, Raul Fretes.

Scotland: Paul Lawrie, Sam Torrance (late replacement for Colin Montgomerie), Gary Orr.

South Africa: Ernie Els, David Frost, Retief Goosen.

Spain: Sergio Garcia, Miguel Angel Jimenez, Jose Maria Olazabal.

Sweden: Gabriel Hjerstedt, Jarmo Sandelin, Patrik Sjoland.