FILE - In this Aug. 27, 2018, file photo, Simona Halep, of Romania, serves to Kaia Kanepi, of Estonia, during the first round of the U.S. Open tennis tournament, in New York.  No. 1-ranked Halep returns to competitive tennis this week at the Sydney International unsure if her back injury has fully healed.
FILE - In this Aug. 27, 2018, file photo, Simona Halep, of Romania, serves to Kaia Kanepi, of Estonia, during the first round of the U.S. Open tennis tournament, in New York. No. 1-ranked Halep returns to competitive tennis this week at the Sydney International unsure if her back injury has fully healed. Andres Kudacki, File AP Photo
FILE - In this Aug. 27, 2018, file photo, Simona Halep, of Romania, serves to Kaia Kanepi, of Estonia, during the first round of the U.S. Open tennis tournament, in New York. No. 1-ranked Halep returns to competitive tennis this week at the Sydney International unsure if her back injury has fully healed. Andres Kudacki, File AP Photo