Lefty's name is on the commitment list, but he's not sure he will make it to the first tee in La Quinta, Calif., on Thursday following two hernia surgeries in recent months.
"It's 50/50 probably, I think," Mickelson said earlier this month, indicating that he probably won't make a decision until perhaps a day before the start of the 58th edition of one of the PGA Tour's most iconic tournaments.
One thing certain is that Mickelson will be on hand for the event on the Stadium Course and the Tournament Course at PGA West, in addition to La Quinta Country Club.
Although he feels honored, he's downplaying his involvement.
"An ambassador is not a host," said Mickelson, who has played in the tournament 13 times. "I'm just really trying to help out. But it is not my tournament. What I am is trying to get this tournament to the status it once had.
"Arnie and Jack Nicklaus, they had their own tournaments. I don't think you should overstate this. Plus, this is just the first year of my involvement. We are just getting started. It is kind of a dip-the-toe-in-the-water right now."
Mickelson won the tournament in 2002 and 2004, putting his name on the trophy next to notable stars such as Palmer, Nicklaus, Billy Casper, Bob Rosburg, Tommy Jacobs, Doug Sanders, Hubert Green, Bruce Devlin, Craig Stadler, Corey Pavin, John Mahaffey, Lanny Wadkins and Jay Haas.
During the early years, most of the best players on the PGA Tour would show up for Bob Hope's tournament, but not so much anymore.
Playing this week are Patrick Reed, Bill Haas, Zach Johnson, Angel Cabrera, Stewart Cink and past champions Mark Wilson, Brian Gay, Jhonattan Vegas, Chad Campbell, D.J. Trahan, Charley Hoffman, Mark Brooks and John Cook.
Not bad, but not what Mickelson believes the field should be.
"I just feel as though the event has a really unique opportunity," Mickelson said. "It's an opportunity to give the players a place to play and play great golf courses in great weather, and build a foundation for the rest of the year. It has a great history, and there is an opportunity to have that return.
"This tournament, just like San Diego (his hometown), means a lot to me. The Farmers Insurance Open (next week at Torrey Pines) has done well. It has a lot of stars in the field and it has added fan attractions and concerts through the years to get people interested. The idea is to create an identity. ... We want to get a few top players in the field as the year starts.
"If we get a few top players, get some top amateurs and in the future some top celebrities out to the tournament, the tournament will be something fans want to come to."
Mickelson also has a sentimental attachment to the event.
While playing at Arizona State he met Amy McBride, a cheerleader for the Phoenix Suns, who would later become his wife.
"It was 1993, my first time at the tournament," recalled Mickelson, who missed the cut in the Bob Hope that year and again it 1994, the only two times he did that in the tournament. "I wasn't much, just a new guy out there on the tour ... but it was the first time I brought Amy along."
Mickelson, 46, is something now, a member of the World Golf Hall of Fame who has won 51 times in his career, 42 on the PGA Tour, including five major titles.
Even though he hasn't won since the 2013 Open Championship at Carnoustie, Lefty finished second three times last year including behind Henrik Stenson in the Open Championship at Royal Troon, where he tied the major championship record with a first-round 63.
Then Mickelson helped the United States regain the Ryder Cup at Hazeltine and tied for eighth at the Safeway Open in October to start the new season before undergoing his first hernia surgery a few days later.
Even if he has to put his ambassador duties on the back burner for a few hours each day.