Rahm, 28, is the No. 1 player in the world heading into the second major of 2023, being hosted at Oak Hill Country Club in Rochester, New York.
He's looking to earn his third career major championship and second of the season after he triumphed at The Masters in early April at Augusta.
A win this week at Oak Hill Country Club would move the Spaniard one step closer to completing the career Grand Slam after he already won the U.S. Open in 2021.
He's coming in with as much momentum as anyone, with four wins already in the current PGA Tour season.
It was there, that Rahm had a funny encounter with LIV Golf's Johnson.
Speaking to reporters Tuesday ahead of the tournament, Rahm was asked if he thought The Masters had helped the coexistence of LIV Golf and PGA Tour players.
It had been the first time in 2023 that the two leagues came together, and there had been much curiosity on how things would go.
However, Rahm said he's "the wrong player to ask."
The question also prompted Rahm to tell a funny story about bumping into LIV Golf's Johnson ahead of the tournament:
Johnson was a long-time Adidas athlete before the two ended their partnership ahead of the 2023 LIV Golf season. Hence, Rahm's surprise by the Footjoys.