Sloane Stephens has stopped working with Paul Annacone following an eight-month partnership, with TENNIS.com's Matt Cronin reporting that she is now being coached by Thomas Hogstedt.

A statement from Stephens' management company called the split "amicable," and the 21-year-old American called it an opportunity for a "fresh start."

Stephens reached a career-high ranking of No. 11 a year ago but has since dropped to No. 22. She has not gone further than the quarterfinals of a tournament this season and lost in the first round of Wimbledon—a defeat that followed six straight Grand Slams where she reached the second week.

Reports at Wimbledon said Annacone and Stephens would end their coaching relationship, and Stephens said the decision had been taken following the tournament.

"Based on the conversations Paul and I had after Wimbledon, we both feel like it would be a good idea for me to have a fresh start leading into the summer hard-court swing," Stephens was quoted as saying. "I've learned a lot over our past eight months together and now just need to meld them into my long-term plan. Paul is one of the top coaches in the world and will remain a close friend and confidant. I can't thank him enough for his time and continued support."

Annacone, who had most recently worked with Roger Federer, cited Stephens' up-and-down play as a reason for the break, and said the timing would allow Stephens to adjust.

"Sloane and I had a lot of good things happen but just couldn't get the desired consistency. And since we agreed that our situation was causing doubt and confusion in Sloane's mind, I really wanted her to find clarity leading into the U.S. Open. This is why a change [now]," he said. "There is absolutely no doubt Sloane is one of the more talented players on the tour and I look forward to watching her have a great deal of success."

Hogstedt is an established coach on the WTA tour, including recent stints with Maria Sharapova (for three years) and Caroline Wozniacki (for three months).

Stephens is expected to have Hogstedt with her at the WTA event in Washington next week.