Retired Hewitt replaces injured Kyrgios for Davis Cup tie

If Hewitt does take part, he will be the first playing captain for Australia since Norman Brookes in 1919.

Lleyton Hewitt may opt to play the doubles rubber against U.S.A if the situation demands.

Veteran Lleyton Hewitt is on standby to break his short-lived retirement if Australia needs its new captain against the United States in this weekend's Davis Cup World Group tie in Melbourne.

World No. 27 Nick Kyrgios withdrew before Thursday's draw with a virus and back trouble, with Hewitt, in charge as Australia captain for the first time, nominated as his replacement.

But Hewitt, 35, who was thought to have played his last competitive match at the Australian Open in January, did not name himself in Friday's singles or Saturday's pivotal doubles rubbers, instead preferring to use 77th-ranked Sam Groth.

Sam Groth to open the tie

Groth will open the tie on grass at Kooyong in Melbourne against big-serving American John Isner, ranked 11, while Australia's top-ranked Bernard Tomic faces world number 24 Jack Sock in Friday's singles. Groth was nominated to partner doubles specialist John Peers in Saturday's showdown against multiple Grand Slam-winners Bob and Mike Bryan.

But that decision can be changed up until an hour before the pivotal rubber, leaving open the possibility that Hewitt could take his place in the doubles. "We'll just see how it pans out," Hewitt said at the draw.

"We've got to put our best options forward every single day and we will have a look at it after each day's play and see how Sam plays and pulls up after his singles."

USA team captain Jim Courier said he was not surprised by the Australian team change. "We've seen how much Lleyton was practising this week and with Nick's pretty conspicuous absence but it's certainly not something coming down here that we were anticipating," Courier said.

If Hewitt does take part he will be the first playing captain for Australia since Norman Brookes in 1919.

Kyrgios practised briefly this week but he was ruled out by team medical staff, having not recovered from a virus he contracted in Dubai last week. "We took Nick through his paces a little bit this morning, just gave him a bit of a fitness test," Hewitt said.

"We had to see how he pulled up from yesterday. It wasn't the toughest hit yesterday but he just wasn't fit enough to play this weekend, which is just unlucky. It was bad timing for us, but it was really out of our hands in the end."

Hewitt announced his retirement amid great fanfare at this year's Australian Open in Melbourne when he bowed out to Spain's David Ferrer in the second round.