This will be Williams' first Fed Cup match 2003.

The U.S. team, which also includes Venus Williams for the first time since 2005, will be heavily favored against a Belgian team missing its top two players. No. 1-ranked Justine Henin and No. 4 Kim Clijsters declined to participate.

Serena Williams pulled her groin in practice April 9, then retired the next day trailing Chan Yung-jan 5-3 at the Family Circle Cup in Charleston, S.C. Williams said she took a few days off before she resumed practicing, and she's feeling much better.

"I figured I was going to play this weekend," she said today. "When I got hurt in Charleston, it wasn't even a second thought in my mind. I just knew I was going to be here."

The loss at Charleston was only the second in 17 matches this year for Williams, who has won the two biggest titles so far — the Australian Open and the Sony-Ericsson Open. She fell to 140th in the rankings last July because of a long layoff but is now 12th.