WIMBLEDON, Great Britain -- With four different teams emerging victorious over the last four Grand Slam tournaments, the doubles field on the WTA is exhibiting an exceptional level of depth that puts numerous contenders in play for the Wimbledon title in 2018.

Defending champions Ekaterina Makarova and Elena Vesnina will not come back as a tandem to attempt to retain their title, as Vesnina withdrew from The Championships due to injury. The Russians, currently co-World No.1s in the WTA doubles rankings, had reached the final in 2015 before triumphing last year. Makarova will instead pair with another compatriot, Vera Zvonareva, as an unseeded team.

In the defending champions' stead, Australian Open victors Timea Babos of Hungary and Kristina Mladenovic of France assume the No.1 seed. The pair picked up their second title of the year on the grass of Birmingham last week, putting themselves as serious contenders to finally win Wimbledon after finishing as runners-up in 2014.

But the top seeds open with a tricky draw, as they face off against the Japanese pairing of Eri Hozumi and Miyu Kato. Hozumi was half of the surprise package of the French Open, as she and another Japanese player, Makoto Ninomiya, raced all the way to the final before falling to Czechs Barbora Krejcikova and Katerina Siniakova.

Krejcikova and Siniakova are seeded No.3 due to their maiden Grand Slam victory, which was five years after they teamed up to win the juniors title in Paris. The Czechs followed up their French Open junior championship in 2013 by winning the Wimbledon juniors as well, and hope that history will repeat at senior level.

Two veteran Czechs, Andrea Sestini Hlavackova and Barbora Strycova, sit at the bottom of the draw as the No.2 seeds. Sestini Hlavackova was a Wimbledon runner-up in 2012, partnering another Czech, Lucie Hradecka. Sestini Hlavackova also won a silver medal at the 2012 Olympics at the All-England Club alongside Hradecka, extending her solid Wimbledon resume.

Rounding out the Top 4 seeds are Andreja Klepac of Slovenia and María José Martínez Sánchez of Spain. Klepac and Martínez Sánchez picked up three runner-up plates earlier in the year before winning their first title of 2018 on grass at the Mallorca Open.

Another notable team is No.8 seeds Elise Mertens of Belgium and Demi Schuurs of the Netherlands. Schuurs has been one of the highlights of the WTA this season: the Dutchwoman has claimed five titles so far this year, with four different partners. She and Mertens have been a solid pair on grass: they won the 's-Hertogenbosch title before falling to Babos and Mladenovic in the Birmingham final.

No.10 seeds Ashleigh Barty of Australia and CoCo Vandeweghe also make an eye-catching pair. Barty has reached the women's doubles final of all four Grand Slam events during her career, but is still looking for her first championship. It could come with Vandeweghe, as they demonstrated they have the goods by winning the Miami Open earlier in the year.

Missing from the field are six-time Wimbledon champions Serena and Venus Williams. The legendary American sisters, who are a staggering 14-0 in Grand Slam doubles finals, will focus on their singles play over the fortnight.

WIMBLEDON LADIES' DOUBLES SEEDS
1.   Timea Babos (HUN) / Kristina Mladenovic (FRA)
2.   Andrea Sestini Hlavackova (CZE) / Barbora Strycova (CZE)
3.   Barbora Krejcikova (CZE) / Katerina Siniakova (CZE)
4.   Andreja Klepac (SLO) / María José Martínez Sánchez (ESP)
5.   Latisha Chan (TPE) / Peng Shuai (CHN)
6.   Gabriela Dabrowski (CAN) / Xu Yifan (CHN)
7.   Chan Hao-ching (TPE) / Yang Zhaoxuan (CHN)
8.   Elise Mertens (BEL) / Demi Schuurs (NED)

9.   Kiki Bertens (NED) / Johanna Larsson (SWE)
10.   Ashleigh Barty (AUS) / CoCo Vandeweghe (USA)
11.   Raquel Atawo (USA) / Anna-Lena Groenefeld (GER)
12.   Nicole Melichar (USA) / Kveta Peschke (CZE)
13.   Kirsten Flipkens (BEL) / Monica Niculescu (ROU)
14.   Lucie Hradecka (CZE) / Hsieh Su-wei (TPE)
15.   Irina-Camelia Begu (ROU) / Mihaela Buzarnescu (ROU)
16.   Lyudmyla Kichenok (UKR) / Alla Kudryavtseva (RUS)