World number one Victoria Azarenka said she only played in this week's Italian Open to avoid a ranking penalty.
The Belarussian won her first match against Shahar Peer but then immediately pulled out of the tournament, citing a right shoulder injury.
On Friday, Azarenka revealed via Twitter that she had been forced into playing in order to protect her position at the top of the world rankings.
"I was conflicted and disappointed to withdraw from Rome," she said. "I tried my hardest but I wasn't healthy going into the tournament.
"If WTA rules were different then I could have focused on getting healthy but I could not afford another zero pointer on my ranking.
"Hopefully in the future there will be more protection for players rights."
A zero pointer means players have to include that particular tournament in their ranking calculations and cannot replace it with another.