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Jarkko Nieminen, Michael Lammer and Ryan Sweeting all called it a career in 2015.

Best of 2015: Player Retirements, Part Two

ATPWorldTour.com recalls the career highlights of four players who retired from professional tennis in 2015

Robin Soderling (Retired: 23 December)
For four years, five months and seven days the tennis world waited for news of Robin Soderling's return. But there was to be no comeback from the severe mononucleosis that deprived him of his tennis prime. The Swede had been unable to play competitively since a 6-2, 6-2 over David Ferrer on 17 July 2011 in the final of the Bastad Swedish Open, which marked his 10th ATP World Tour title. Soderling started to develop a fever and sore throat at Wimbledon in 2011, but rallied to play what was to be his final matches a couple of weeks later in Bastad. He was 26 years old.

Blessed with a powerful game and a heavy serve, the majority of his best results came on hard and indoor courts, yet it was on the clay of Roland Garros in 2009 and 2010 that Soderling proved his mettle with back-to-back final appearances. His four-set fourth-round win in 2009 over the unbeaten Rafael Nadal, ending the Spaniard's 31-match winning streak at Roland Garros, reverberated around the tennis world. To date, he remains one of only two players (Novak Djokovic, 2015) to beat Nadal on Parisian clay. He beat Roger Federer en route to the 2010 title match.

Soderling also enjoyed success across the French capital in late 2010, when he became the first Swedish player to win an ATP World Tour Masters 1000 title since Thomas Enqvist in 1996. It ensured he rose to a career-high No. 4 in the Emirates ATP Rankings on 15 November 2010. As he battled to regain fitness, Soderling launched a new range of tennis balls under the brand 'RS-Tennis' in 2013 and last year he was named the Stockholm Open tournament director. Aged 31, he called time on his playing career.

Jarkko Nieminen (Retired: 21 October)
Jarkko Nieminen, a role model to so many young players on the ATP World Tour, became the standard bearer for Finnish tennis over 16 years as a professional and assured himself of a playing in his nation's sporting history, alongside the likes of Janne Ahonen, Mika Häkkinen and Sami Hyypiä.

Renowned for his speed, Nieminen was a dangerous foe capable of battling against the very best on every surface, as evidenced by victories over current or former World No. 1s, including Andre Agassi, Yevgeny Kafelnikov, Carlos Moya, Marat Safin, Juan Carlos Ferrero and Novak Djokovic. He recorded 405 singles match wins and ranked in the year-end Top 100 since 2001. "I always had faith in myself, but I kept my feet on the ground," said Nieminen, who was also a member of the ATP Player Council from June 2010 to June 2014.

He rose to a career-high No. 13 in the Emirates ATP Rankings on 10 July 2006, shortly after he appeared in the Wimbledon quarter-finals, one of three last eight showings at major championships (also 2005 US Open, 2008 Australian Open). He reached 13 ATP World Tour singles finals, winning titles at 2006 Auckland (d. Ancic) and 2012 Sydney (d. Benneteau) and was also 5-4 in doubles finals.

Ryan Sweeting (Retired: 20 August)
For Ryan Sweeting, a former junior World No. 2 and 2005 US Open champion, his pro career promised much, but the transition from junior to senior tennis is fraught. Aged 23, he won his only ATP World Tour title against Kei Nishikori at Houston in April 2011, and on 12 September that year rose to a career-high No. 64 in the Emirates ATP Rankings. Yet the Bahamian-born American was hindered by a back injury that forced him off the ATP World Tour for extensive periods.

Michael Lammer (Retired: 14 March)
Michael Lammer played the final match of his career with Roger Federer, his friend of 25 years, at the ATP World Tour Masters 1000 event in Indian Wells. He rose to a career-high No. 150 in the Emirates ATP Rankings on 9 November 2009, the year he captured his only ATP World Tour doubles title (w/Chiudinelli) at Gstaad. He was also part of Switzerland's Davis Cup winning team in 2014.

Read Part 1: Best of 2015 Player Retirements - Fish, Ginepri, Russell