She has dumped swing coach Ted Oh on the eve of defending her Mediheal Championship title – and it's one change too many according to former coach David Leadbetter.
Leadbetter, who coached Ko from 2013 to 2016, oversaw the 22-year-old's rapid rise to the top of women's golf.
However, those early years - where Ko took out two majors and held the world number one spot for 84 weeks - now feels like an age away.
Speaking to Radio Sport's D'Arcy Waldegrave, Leadbetter said it has been sad to see Ko's downfall.
"From my standpoint it's ancient history now and it's just sad to see that Lydia has not continued along the path she was going on," said Leadbetter. "Obviously by her standards are concerned, she's certainly struggled the last couple of years.
"Considering, I would say, her start in professional golf was probably hotter than Tiger [Woods]'s, it's obviously going to be very deflating for her and obviously they want to try somebody else. They're falling fast these coaches, aren't they?
"Unfortunately it seems everything is muddled in her mind. Whether she's being directed in the right way, whether she's getting the right advice, whether it be parents or your advisers, I don't know.
"But it's just sad to see because as good as she was, as great a player as she was, she's a good player still but she's sort of back in the pack now."
Last year's victory at the Mediheal Championship was Ko's 15th of her career, but the only one since Oh took on the role in February 2018.
"We just mutually decided that it was time," Ko told the Golf Channel.
"We ended on good terms ... I have a lot to thank Ted for. He gave me a really solid blueprint simplifying my swing."
Leadbetter said he believes making too many changes is one of the main reasons behind Ko's recent form troubles.
"You look at somebody like a Jordan Spieth, I mean look he's going through some terrible times recently but he and his coach are trying to work it out and that's what you try to do.
"You try to find that little magic again and it was just very sad towards the end of 2017 where she decided because she had a poor last couple of months that she wanted to try something different.
"And boy did she try something different from equipment, to coaches, to caddie, to workouts, her fitness coach, to her mental coach.
"I just think when you make all these changes, it's a shock to the system. Sometimes it can work certainly, but a lot of times it won't. Unfortunately it's trying to find that magic again which she had. She was a very special player."
Leadbetter pointed to several technical areas in Ko's game that have suffered since the big changes, including her ability to hit greens, a previous strength of hers.
"The thing that's most noticeable which is very important as far as statistics are concerned is her greens and regulation.
"She was always right up there in greens and regulation, up near the top. And now she's way down. It puts a lot of stress on the rest of your game. She's not hitting a lot of fairways, but I think the biggest problem is that she's not hitting a lot of greens.
Leadbetter also said changes to her swing, as well as pushing herself too hard, may have contributed to Ko's decline.
"Paige MacKenzie who is a former tour professional herself, she came out and said 'I think her swing looks better'. Well it's form over function isn't it.
"I mean the fact that she had a very functional swing and towards the end of 2017, in my opinion, she was absolutely exhausted – she went through the Olympics etc. – and I think she should've taken probably a lot of time off, but she played.
"And when you play through fatigue and stress, as I think there was after the Olympics – I mean she did an amazing job winning herself a medal – and the rest of the year was pretty much a write off."
Lydia Ko's coaches since going pro
• David Leadbetter Ko's swing coach from 2013 until the end of 2016.
• Gary Gilchrist - in early 2017, out early 2018.
• Ted Oh - Gilchrist's replacement, taking over in early 2018 until this week.
