Lee Westwood is scheduled to face Ryder Cup rival Phil Mickelson in the most eye-catching first round tie.

Westwood was initially drawn to face world number three Ernie Els when the 64-man field for the event was decided by the official world rankings seven days ago.

But the withdrawals of Els, US Open champion Jim Furyk and American Kirk Triplett has meant a reshuffle of the entry list and paired Westwood and Mickelson together.

The draw will not be made official until late this afternoon local time, and any player who withdraws before then will be replaced in the draw. After that time, their scheduled opponent will receive a bye into the next round.

Barring any such withdrawals, Wednesday’s first round will see two of the game’s most revitalised players go head to head at La Costa.

Westwood had failed to win in almost three years and slumped from fourth in the world to 215th before his victory at the BMW International Open last August.

The former European number one then claimed the Dunhill Links championship a few weeks later and is now back within sight of the world’s top 50 and seems certain to qualify for the Ryder Cup in September.

Mickelson’s fall from grace was not quite so dramatic but the left-hander had dropped out of the world’s top 10 for the first time in several years until rediscovering his form this year with a win on the US Tour.

Colin Montgomerie, who has come straight from the Malaysian Open, is up against Zimbabwe’s Nick Price while the only all-European tie pits Swede Fredrik Jacobson against Ryder Cup hero Phil Price.

Paul Casey faces a tough opening contest against USPGA champion Shaun Micheel and Seve Trophy team-mate Ian Poulter takes on American Chris Riley.

Woods will begin the defence of his title against John Rollins and could face Thomas Bjorn in the third round if the Dane gets that far, Scott Hoch is first in line for the Open runner-up.