The Serbian has battled since reaching the fourth round at the US Open, and will be desperate to return to her best as the Asian swing continues.
Jankovic has just one win in three tournaments since Flushing Meadows, where she was beaten by teenager Belinda Bencic.
At number 11, she is the highest ranked player at the WTA International event played on hard courts in China.
Her US Open conqueror – Bencic – is the third seed.
The Swiss 17-year-old has also been in indifferent form since the final grand slam of the year, but a weaker field shapes as an opportunity for her to go on a run.
Locals Peng Shuai and Zhang Shuai are also in the field.
Peng was beaten by Petra Kvitova in the second round in Beijing, while Zhang is winless since Cincinnati.
Since reaching the semi-finals on grass at Birmingham, Zhang has a disappointing 1-7 win-loss record.
Americans Varvara Lepchenko and Alison Riske, Puerto Rican Monica Puig and Croatian Ajla Tomljanovic are also competing.
Lepchenko, runner-up in Seoul, has failed to get through qualifying at two events since.
Riske has endured a poor year, Puig has struggled since winning the Strasbourg title in May and the hard-hitting Tomljanovic has been underwhelming.
With a weaker field, Tianjin shapes as an opportunity for several players to try and finish the season strongly.