Stuttgart - Former world number one Dinara Safina admitted on Monday that a repeat of the back injury that has kept her out of tennis since January could potentially end her career.
Safina, who turns 24 on Tuesday, is the second seed at Stuttgart's WTA tournament but has not played since January's Australian Open when she was forced to retire at the fourth round stage because of a painful back injury.
An examination later revealed she was suffering from a double stress fracture and a ruptured muscle in her back.
Currently the world number three, the Russian has been receiving intensive treatment since her set-back in Melbourne but admits she is returning with some trepidation to Stuttgart where she was last year's beaten finalist.
"I am glad to be here, this is my first big test after having come back from my injury," Safina, who was world number one exactly a year ago, told reporters.
"My physio is here and I really want to take it step by step.
" I only started playing on court again on April 3.
"Everybody, including my brother Marat (Safin), told me to take my time but it was really difficult because I wanted to come back on court so badly.
"Right now I feel safe and comfortable, but I need to watch closely that it stays that way.
"My back injury is the worst you can get, because if things go wrong again, that might be it for my professional career altogether."
Safina says her enforced break from tennis has made her realise how much she loves the game and plans to play on for as long as possible.
"There is no way that you can go easy on a lower back injury," she said.
"With a broken arm or leg, you can rest it, but with your back it is almost impossible. It has made me realise how much I love tennis.
"I just want to get back on court.
"Regarding things like rankings, titles, defending points - who really cares?"
Both former number ones Venus Williams and Kim Clijsters have withdrawn from the tournament with injury, but defending champion Svetlana Kuznetsova says she is happy to be back to get some clay-court practice ahead of Roland Garos.
"I love this tournament, it is one of the best on the tour," said the 24-year-old with the French Open set to start on May 23.
"The clay surface indoors is slippery and different from outdoor clay, but I like it that way.
"I do not think of points to defend, rankings or the possible final. These questions I block out completely, I take one match at a time."
The top half of the Stuttgart draw features top seed Caroline Wozniacki, the world number two who has a bye, and she is expected to face Victoria Azarenka in the quarter-finals.
But Kuznetsova and Australia's Samantha Stosur are potential opponents she may need to overcome if she is to reach the final.
In the bottom half, Safina has an opening bye but is potentially up against the likes of Ana Ivanovic and Jelena Jankovic, while Belgium's Justine Henin faces Germany's Julia Goerges in her first match.
Competition in the Porsche Arena promises to be tough with a total of seven top ten players appearing at the 33rd edition of the long standing event, a key warm-up for the French Open next month.