TORONTO — Canadian sprint star Andre De Grasse has switched coaches in hopes of turning around a career derailed by injuries.

The three-time Olympic medallist is working with Rana Reider in Florida, leaving Stuart McMillan and the Altis group he'd been with since turning pro in December 2015.

"I felt like the time was right to make a change," De Grasse said in an email to The Canadian Press. "Coach McMillan is a great coach and we had a lot of success together, but the past two years haven't gone the way we hoped so we decided the best thing to do was make a change."

De Grasse's much-anticipated rematch with Usain Bolt at the 2017 world championships made international headlines, but the Canadian was forced to withdraw just days before the meet in London with a hamstring injury. He was then forced to shut down early last season when he suffered another hamstring strain to the same leg at the Canadian championships in Ottawa, slowing to a walk with about 40 metres to go.

The 24-year-old from Markham, Ont., hopes the switch will help him get back to top speed in a busy upcoming season that includes the world championships in Doha, Qatar and the Pan American Games in Lima, Peru.

"The coach I decided to put my faith in is Rana Reider," De Grasse said. "He has an incredible history of success with athletes from all events. He had moved back to Florida from Europe to be close to his family so I decided to make the move to work with him in Florida.

"The climate is perfect for training and the university we are training at was very accommodating, so it made the decision very easy."

Reider recently returned to the United States after coaching a group in the Netherlands that included Dutch sprint star Dafne Schippers. De Grasse is training with Reider at the University of North Florida in Jacksonville.

De Grasse burst onto the international scene when he won double Pan Am Games gold in 2015 and bronze at the world championships later that summer. He captured silver in the 200 metres at the 2016 Rio Olympics and took bronze in both the 100 and 4x100 relay.

"2016 was an amazing year, culminating in a very successful Rio Games," McMillan told The Canadian Press on Friday. "It has been very challenging since then, and the results have not been what any of us would have expected or hoped for. It became clear that Andre needed a change, and I wish him and his new coach the best of luck.

"I expect he will be back to the best very soon, and will be battling for a spot on the podium in Tokyo (Olympics) in 2020."

De Grasse had been touted as the world's next big sprint star when he turned pro, signing a multi-year deal with Puma worth about $11.25 million. It was the most lucrative initial contract in track and field history.

He hasn't raced since the Canadian championships last July, and had said he was taking the break to enjoy time with his daughter Yuri, who was also born in July.

De Grasse said he's back to full health now, but will skip the indoor track season and make his season debut in the spring.