The Victoria batsman Rob Quiney will make his Test debut against South Africa at the Gabba on Friday after Shane Watson was ruled out due to a calf injury. Watson suffered the problem while bowling for New South Wales in their Sheffield Shield match against Queensland on Saturday and although it will not heal by this Friday, Australia's coach Mickey Arthur is hopeful Watson will be able to play as an allrounder in the second Test at the Adelaide Oval.

"Shane Watson won't play the first Test match. He did an assessment this morning. We've ruled him out," Arthur said in Brisbane on Monday. "We're hoping that he will play unrestricted in the second Test match at the Adelaide Oval. That means Rob Quiney makes his debut this week against South Africa.

"We're ruling him out now because we think he won't be fit enough come Friday. We wanted to be really decisive. We didn't want this to outplay the whole week. We wanted to make a decisive decision pretty early so we could give some real clarity to the team. I think we've done that. Unfortunately Shane misses out."

Quiney will bat at No.3 in a direct swap for Watson, who was unable to play any part in Australia's home Tests last summer due to calf and hamstring problems. Watson has two and a half weeks to prove his fitness for the second Test in Adelaide and while Arthur believes there is a good chance he will be available for that match, he was confident Australia had enough depth to cover Watson's absence in the battle for the No.1 Test ranking.

"Last year we won 4-0 against India, Shane Watson wasn't part of that side over the summer," he said. "We're relaxed, we're calm. I think the team is all in a really good space. We're comfortable that we have the players, we have the cover."

There was also some good news for the Australians on Monday, with Ricky Ponting declared a near-certainty to play after withdrawing from Tasmania's Sheffield Shield game on Friday due to hamstring soreness. But Watson's absence will throw out the balance in Australia's side, depriving Michael Clarke of a valuable fourth seam-bowling option.

Although that could have encouraged the selectors to lean towards including four specialist fast bowlers and relying on Clarke for some overs of spin, Arthur said after discussing the pitch with the Gabba curator Kevin Mitchell on Monday it was likely the offspinner Nathan Lyon would play.

Lyon has not enjoyed his finest form for South Australia over the past few weeks, collecting six wickets at the inflated average of 68, but he should enjoying returning to the Gabba after he took seven wickets there in last year's Test against New Zealand. Arthur said although Lyon might need a confidence boost ahead of the Test, he believed he would play a significant role against the South Africans.

"We've still got to go and see what the wicket delivers for us," Arthur said. "Michael, myself and [team performance manager] Pat Howard had a meeting this morning with the curator. We're pretty confident we're going to get a very, very good Gabba wicket, which increases the likelihood of us playing a spinner.

"We've never ever doubted Nathan's ability. We're hoping that when he comes into this environment, and I know South Australia have done some very good work with him… he gets the lift that he needs. We're backing Nathan Lyon at the moment. Michael, myself and the selection panel believe that Nathan Lyon is our best spinner and Nathan Lyon will be our best spinner for a long period of time. We want to give him that confidence and back him in."