The WTA off-season coaching carousel is in full effect. Here's a roundup of the biggest announcements so far, which includes a number of high-profile splits and reunions. 

This post will be continually updated with additional team changes. 

Madison Keys hires Jim Madrigal.

Madison Keys' coaching search is over. The 23-year-old American has hired former ATP coach Jim Madrigal as her new coach.

After announcing the end of her coaching partnership with Lindsay Davenport in June, Keys had a brief stint with David Taylor before opting to go solo for the remainder of the season. Without a head coach in place, the World No.17 made her second Slam semifinal of the season at the US Open and finished her year by qualifying for the semifinals at the WTA Elite Trophy Zhuhai before being forced to retire due to a left knee injury.  

Keys is scheduled to start her 2019 season at the Australian Open. 

Elise Mertens joins forces with David Taylor

Belgium's No.1 will start the 2019 season with a seasoned coach in her corner. Mertens was previously coached by Dieter Kindlmann, while Taylor spent the last two seasons coaching Madison Keys, Jelena Ostapenko, and Naomi Osaka. 

After a breakout season that saw her finish at a career-high No.12, the 23-year-old will be under pressure at the start of the season to defend her results in Australia, where she enjoyed a 9-match win streak to start her 2018 season, winning the Hobart International before making the Australian Open semifinals. 

Mertens's first scheduled tournament is the Brisbane International.

Venus Williams and David Witt end their 11-year partnership.

David Witt is back on the market. The longtime coach and hitting partner for Venus Williams told The New York Times that the two have ended their partnership before the pre-season. Venus' first confirmed tournament is set to be the ASB Classic in Auckland. 

More previously announced coaching moves: 

Angelique Kerber hires 2003 Australian Open finalist Rainer Schuettler

One of the most significant open coaching positions has now been filled. Kerber's sudden announcement of her split with coach Wim Fissette before the BNP Paribas WTA Finals Singapore presented by SC Global came as a surprise given the pair's 2018 success, but the reigning Wimbledon champion has her new team in place with the hiring of former ATP No.5 and 2003 Australian Open finalist Rainer Schuettler as head coach. 

“I am really looking forward to the opportunity of working with Angelique during this phase of her career," Schuettler said in a statement. "She has obviously shown what a great champion she is and I hope my experience can bring a fresh perspective to an already strong team.”

Schuettler, 42, will officially join Team Kerber when the World No.2 begins her pre-season training at the end of November.  Kerber is scheduled to begin her WTA season at the Sydney International. 

Darren Cahill to take a 12-month hiatus from coaching Simona Halep

In another split that few saw coming, Darren Cahill announced he is taking a break from coaching to spend more time with his family. More on the amicable Halep-Cahill split here

Halep has yet to name a replacement. 

Victoria Azarenka reunites with Wim Fissette

The former World No.1 is set to continue her charge back up the rankings. Fissette split with reigning Wimbledon champion Angelique Kerber last month, creating a perfect opportunity to pick up where he left off with Azarenka.

The Belarusian has reunited with the man who was at the helm when the two-time Australian Open champion pulled off a blistering start to her 2016 season. Azarenka and Fissette began their initial partnership in February of 2015 after Fissette split with Simona Halep and Azarenka was ranked No.50. The following season, Azarenka won Brisbane, made the quarterfinals of the Australian Open, and then pulled off the 'Sunshine Double', winning Indian Wells and Miami back-to-back to return to the Top 5, before subsequently ending her season to go on maternity leave.  

Azarenka's limited 2018 season saw her start outside the Top 200 and finish at No.51. 

Elina Svitolina promotes Andrew Bettles

The 2018 WTA Finals champion has quickly answered the question that seemed to linger over her phenomenal run to the biggest title of her career last month: Why not Andy?

Bettles has served as Svitolina's hitting partner and traveling coach through much of the last two seasons, during which time Thierry Ascione served as her head coach. Svitolina announced her split with Ascione after the US Open and Bettles served as her primary coach for the remainder of the season.

Prior to working with Svitolina, the 25-year-old Brit also served as a hitting partner for Ana Ivanovic before the Serbian retired in 2016.

Johanna Konta makes it permanent with Dmitry Zavioloff

After splitting with Michael Joyce in early October, the British No.1 brought on Zavioloff, who previously coached Timea Bacsinszky and Stan Wawrinka, for a trial period. Konta has confirmed the two will continue together in 2019. 

Konta began the 2018 season ranked No.9 and finished ranked No.39.

Eugenie Bouchard picks up Michael Joyce

The 24-year-old Canadian finished the 2018 season ranked No.89 and picked up Joyce after the veteran coach split with Konta. 

Kiki Bertens adds Elise Tamaela to coaching team

After finishing her incredible 2018 season as the first Dutchwoman since Betty Stove to finish the season inside the Top 10, Bertens announced she would be adding former player Elise Tamaela to her team as a part-time coach and traveling physio. Tamaela stepped in for Sluiter as Bertens' coach during her title-run in Charleston earlier this season. Tamaela joins a solid team that includes full-time coach Raemon Sluiter and physio Remko De Rijke.

Maria Sakkari hires Mark Petchey

After announcing her split with Thomas Johansson at the end of the season, No.41 Sakkari has brought on Mark Petchey as her new coach for 2019. A former coach to Andy Murray, Petchey has most recently served as a commentator for Sky Sports, BBC, and ITV. 

Belinda Bencic splits with Vladimir Platenik

After a strong 12 months that saw her re-enter the Top 100 after injuries set her back, the Swiss prodigy has ended her partnership with Platenik. The Slovakian coach, whose past players include Dominika Cibulkova and Daria Kasatkina, also confirmed he is no longer working with 21-year-old Ukrainian Anhelina Kalinina. 

Sam Stosur ends her partnership with Josh Eagle

The Aussie announced on Twitter that her two-year partnership with Eagle is over. The 2011 US Open champion has hired her childhood coach Nick Watkins to start the 2019 season. 

Notable coaching hires: Petar Popovic, who previoulsy coached Andrea Petkovic and Ivo Karlovic, will coach Serbian teen Olga Danilovic in 2019.... After splitting with Timea Babos, Thomas Drouet will coach 20-year-old Russian Anna Blinkova... 2013 Wimbledon champion Marion Bartoli jumps into the coaching game, announcing she'll coach 19-year-old Frenchwoman Lucie Wargnier.

This post was last updated on December 14, 2018.