LA QUINTA, Calif. – At the 1999 U.S. Open Phil Mickelson had his then-caddie, Jim Mackay, carry a pager in case Lefty’s wife, Amy, went into labor with the couple’s first child during the final round at Pinehurst.

This week at The American Express, where Mickelson is the host, he will have his swing coach, Andrew Getson, on his bag while his regular caddie, his brother Tim, is at home with his wife for the birth of the couple’s first child.

“I'm very excited for them, but with Palm Springs being a two-hour drive [from Tim Mickelson’s home in Scottsdale, Arizona] and the inability to join your wife if you're not with her when you go into the hospital at birth, he has to be there with her,” Mickelson said. “They're due any minute, any day, and I'm excited for them.”

Getson caddied for Mickelson at last year’s Genesis Invitational and he has been working with Lefty for over five years.

“On Tuesday [Getson] was Thursday ready," Mickelson said. "His game is sharp, he is working hard, he's going to be a great caddie and I'm appreciative of him stepping in to take-over for my brother."