- 2017 the year of tennis comebacks
- Federer returns from knee injury
- Sharapova returns from drug ban
- Nadal, Serena also return from injuries
(CNN)If 2016 was a season of memorable firsts in tennis, call 2017 the year of the comeback. Roger Federer, Maria Sharapova, Serena Williams and Nick Kyrgios -- and there are more -- are among those returning to the circuit after being sidelined for differing reasons.