Watson last night was diagnosed with a minor quadriceps strain that does not require Australia to send for a replacement.
"I think it's going to be very hard to knock him out. He batted absolutely beautifully in his first Test in Johannesburg in really tough conditions so he got his hundred on debut. If I did that, you'd expect to get a good run at it," Watson said.
"My expectation is that it's going to be unbelievably hard to dislodge him at the moment because he's been able to perform when he's got that opportunity. If and when I get an opportunity in the tour matches or whenever it is, I've got to perform," The Age quoted Watson, as saying.
The Australians decided against sending Brad Hodge, and the selectors may be more inclined to look to a county batsman such as Chris Rogers or David Hussey if temporary cover is required.
Captain Ricky Ponting said Watson could play as a batsman if required, if his injury kept him from bowling before the first Test.
"If we happen to have a batter hurt themselves in this game, we could be a little bit short. We certainly have to consider that. Shane was probably picked as the spare batter on the tour anyway," Ponting said.
Watson was injured during the heavy training that followed Australia's early elimination from the Twenty20 world championship, which was designed to put miles in the legs of the quicks and included some punishing fitness sessions. (ANI)