The 28-year-old Sorana Cirstea has finished inside the top-100 for the 10th time in the last 11 years but she failed to repeat her results from the last season, winning just 14 matches in 2018 and reaching the quarter-final only twice.
The Bucharest native had a packed schedule in the opening three months but she was forced to reduce her calendar in the remaining months of the season, playing just seven tournaments after Wimbledon but struggling to find the form and the results.
Preparing for the new season, Cirstea has decided to withdraw from the Romanian Fed Cup team after 12 years of serving, focusing on her WTA results and creating the best possible schedule in 2019. Sorana made her Fed Cup debut back in 2006 against Sweden just a few weeks after turning 16 and she competed in 29 rubbers, winning 11 out of 16 Fed Cup singles matches and having a chance to play against Agnieszka Radwanska, Jelena Jankovic and Ana Ivanovic.
Romania stayed in Group I for almost 10 years before winning seven straight ties in 2014-15 to reach the World Group where they will play in 2019 as well, facing the defending champions the Czech Republic in the first round in February.
"After 12 years of playing for Romania, it is time to officially announce my withdrawal from the national Fed Cup team. I made the debut in the national squad at the age of 16 as the youngest debutant in the Romanian Fed Cup history and I have been representing my country with pride and honor every time I had a chance to play.
I feel like I have done my duty and now is the time to pass the relay baton onto new generation! I would like to thank my teammates, the Federation, the captains, the coaches and everyone who was involved in our success, and especially the Romanian crowd that has been supporting me over the years."