Petra Kvitova has regained the use of her racquet hand but there is still no "concrete date" for her return after a knife attack at her home in December.
Kvitova, 27, was stabbed by an intruder in Prostejov in the Czech Republic.
Doctors had said the 2011 and 2014 Wimbledon champion would be unable to compete for at least six months.
"Petra's recovery is continuing as planned, but everything is up in the air as to her return," her spokesman, Karel Tejkal, told AFP.
Tejkal said Kvitova's psychological recovery had been "very encouraging" and that she had been fitness training in the Canary Islands.
"Petra uses her hand without problem for daily activities. Of course, the hand is weakened but at first glance you can't see that she was injured," he added.
"But at the moment no-one can give a concrete date."