"I don't understand what the point is?" – Sock's confusion over Agassi joining Rune's team

Coach changes have become commonplace in high-level tennis. Raducanu, Tsitsipas, and even Monfils have all switched coaches this year. But that’s not all—on top of these changes, many players seem to be implementing trial periods, as seen with Holger Rune.
Indeed, the Dane was spotted with former champion Andre Agassi while preparing for Washington. Although the eight-time Grand Slam winner hasn’t been officially confirmed as a new addition to the player’s team, he did spend several days with the world No. 8. This situation left American Jack Sock baffled:
"I don’t understand why so many players are doing this trial period with their coach. What’s the point of a three-day trial? I feel like Agassi was already working with him before Washington. I really don’t get it."
Meanwhile, Rune’s camp stated that "it’s not about adding a superstar coach to his team, but rather seeing if there’s chemistry, if he can bring a fresh perspective and his experience to the project," as reported by Open Court.
Unfortunately, Rune couldn’t apply his elder’s advice, as he withdrew from the American tournament due to a back issue.