Steffi Graf returns to Croatia's Mirjana Lucic during their Women's Singles, semifinal match on Wimbledon's Number One Court in a July 3, 1999 photo. The 22-time Grand Slam singles champion is interrupting her retirement on Tuesday July 12, 2005 to play with the Houston Wranglers of the World Team Tennis Pro League. (Agencies)

Steffi Graf is returning to the tennis court for the first time in six years, but don't call it a comeback. The 22-time Grand Slam singles champion is interrupting her retirement on Tuesday to play with the Houston Wranglers of the World Team Tennis Pro League.

"It's hard for me to call it a comeback," Graf told The Associated Press in a telephone interview. "It's too early to say if there will be more. It's hard with all the schedules. If it works out, maybe there is another one."

Tuesday's match is Graf's only one this season as a member of the Wranglers. Houston will take on the Sacramento Capitals, led by Anna Kournikova at Houston's Westside Tennis Club.

Much has changed in the 36-year-old Graf's life since she retired in August 1999 as the third-ranked player in the world.

She married Andre Agassi and had two children — a boy in 2001 and a girl in 2003.

"Time is a big factor," Graf said. "For a few years, I barely played. It's not easy with my husband still on tour. It's been a challenge to stay in shape."

Graf, who won 107 career singles titles, said juggling the demands of motherhood and her charity work made it difficult to establish a strict training regimen.

"This year I just picked up the racket more frequently than I have in the last five years," she said. "I've practiced quite a bit the past two weeks, but before that it was very sporadic ."

The 36-year-old German had what is widely considered her best year in 1988, when she won all four Grand Slam singles events in a year and also won an Olympic gold medal.

She acknowledges being "very nervous" about the match but also excited about her return.

"It's huge that she is putting her toe in the water," said Ilana Kloss, WTT chief executive officer and commissioner. "I think she's going to see how she feels. ...but we're absolutely thrilled to have her."

Graf said the generosity that Wranglers owners Jim and Linda McIngvale have shown to her and Agassi's foundations over the years was a major factor in her decision to play again.

Graf played an exhibition match last year in Germany against Gabriela Sabatini.

Graf said she has been trying to strengthen her knees and back after suffering several injuries during her playing career.

She's looking forward to playing in front of a crowd in the fan-friendly format of the WTT, but she cautioned against high expectations.

"How can I be the same," she said. "I live a different lifestyle in general. I think they will see that I'm a little more relaxed than I used to be.

"It will be interesting to see how it's going to work tomorrow (Tuesday)."

The WTT league is made up of 12 teams and plays a three week season ending July 24. The two top teams from each of two conferences advance to the finals Sept. 16-17 in Sacramento.

The coed league, co-founded by Billie Jean King, is in its 30th season.

(Agencies)