Naomi Osaka, Simona Halep and more have already made post–US Open coaching changes. (AP)

With all four Grand Slams in the books, the 2019 tennis season has just a few more major things to take care of: primarily, the Asia swing, the year-end championships, the Davis and Fed Cup finals and, of course, the Coaching Carousel. Players looking to make a move next season will start this fall by hiring and firing coaches, passing them around until it's hard to remember who's working with whom. 

It can all be a lot to keep track of, so here's a list of some notable changes so far: 

Out: Jermaine Jenkins

Jenkins joined Osaka late in February, replacing Sascha Bajin after his seemingly abrupt dismissal. Jenkins' six months on the team were relatively rough ones for Osaka on the court; she couldn't defend her titles in Indian Wells and at the US Open, and she didn't make any tournament finals. 

In, for now: Leonard Maxime Francois

In the meantime, Osaka's been coached by her father, and she's already seen some success. In her first tournament since the change, she won the Premier-level Pan Pacific Open, in Osaka, Japan, without dropping a set. 

In: Darren Cahill

Cahill and Simona Halep have long been one of the better-known player-coach power pairings, but, at Wimbledon this year, Halep showed she could win without him. With that in mind: Cahill is now back on the team, and Halep has to be considered as a big a threat as ever in 2020. 

In: Sam Sumyk

After a brief experiment with Rob Steckley, Anastasia Pavlyuchenkova has been coached in Asia by Sumyk, best known for his success with Victoria Azarenka and Garbine Muguruza. Pavlyuchenkova won eight consecutive sets to reach the final in Osaka. 

 
 
 
 
 
 
 
 
 
 
 
 
 

Told Sam to look like he owns the jet????

A post shared by Anastasia Pavlyuchenkova (@nastia_pav) on

Out: Olivier Jeunehomme

After her Wuhan win over Karolina Pliskova on Wednesday, Dayana Yastremska, who has three WTA titles to her name at age 19, was pegged by Chris Evert as a player to watch in 2020. Two days later, Yastremska announced that she'd done it without her coach. This perhaps makes room for a major name to join one of tennis' most-hyped players this fall. 

In: Carlos Rodriguez 

Amanda Anisimova has been dealing with the unexpected loss of her father, who played the role of coach in her quick rise to the top. She most recently worked with Jaime Cortés. The teen has returned to action in Asia, losing in the second round in Wuhan and first round in Beijing. 

The biggest events of the year may be over, but there's still an awful lot of time between now and the Australian Open, so there will certainly be more Coaching Carousel news to come.