Reuters - After controversially missing the Rio Olympics, Nick Kyrgios has pledged his commitment to Australia's Davis Cup team ahead of their World Group play-off against Slovakia.

The 21-year-old firebrand withdrew from consideration for the Rio tennis tournament after being publicly upbraided about his conduct by team chef de mission Kitty Chiller.

Kyrgios on Tuesday was still battling to shrug off a hip injury which ended his US Open campaign, although he trained with the team ahead of the weekend's tie at Sydney's Ken Rosewall Arena.

"I wouldn't be here if I didn't want to play," he told reporters. "I feel ready. I'm playing probably the best tennis I have.

"I've hit twice since I've been here and been going for about an hour to an hour and a half so it's feeling good and I'm feeling confident (despite the injury)."

World No. 15 Kyrgios was named in the squad to take on Slovakia and if fit, will play in the singles rubbers. Australia's other singles player will be Bernard Tomic, who also withdrew from Rio after a public warning from Chiller.

The tennis players had a minor feud in March when Tomic questioned Kyrgios for pulling out of the World Group tie against the United States in Melbourne due to a "flu-like illness".

On Tuesday, each moved to allay concerns about any lingering bad blood. "He's a great player, with great potential and doing great things," Kyrgios said of world No. 21, who crashed out of the US Open in the first round and was heavily fined for a crude outburst directed at a heckler in the crowd.

Tomic said he and Kyrgios would be long-haul Davis Cup players. "Obviously this is a new week. We're excited and I'm sure everyone else is and I'm sure it's something that has many more years to come."