#2 Maria Sharapova

Russian Maria Sharapova began the year ranked a lowly 60. She made the third round of the Australian Open where she lost to Angelique Kerber in straight sets. She featured in the Qatar Open but was eliminated in the opening round itself. Injuries started to plague her season soon after as she withdrew from the Dubai Open. Another disappointing loss in the 1st round in Indian Wells followed by a forearm injury meant that her ranking was again beginning to slide.
Her run to the semi-finals at the Italian Open meant that she cracked the WTA top-30 for the first time since her return from suspension. A quarter-finals finish at Roland Garros followed. A first-round loss at Wimbledon and a first-ever night session loss in her career at the US Open though took the shine away from her comeback. She skipped the rest of the season due to a shoulder injury and finished the year ranked 29.
The 5-time Grand Slam champion surely has it in her to scale the heights which she achieved prior to her doping ban. 2019 will be the make or break year for her as she is now past 30.