Serena Williams is keen to play for the United States in their first-round Fed Cup tie against Belgium later this month despite spraining her left ankle on Friday.

The former world number one is scheduled to join sister Venus, world number one Lindsay Davenport and Corina Morariu for the April 23-24 tie.

However, she faces a race to get fit in time for the showdown at Delray Beach, Florida, after spraining her ankle during the quarter-finals of the Amelia Island Championship against Italian Silvia Farina Elia.

"I don't think I'll be questionable (for the Fed Cup)," Serena said in a statement released by the WTA Tour on Saturday.

"I am still planning on playing Fed Cup and hopefully it will be okay."

The 23-year-old is set to undergo intensive physiotherapy and will make a final decision nearer the time.