Fast bowling great Glenn McGrath believes selectors must resist temptation and not use Shane Watson as a specialist batsman despite his injury woes, comparing him with champion South African allrounder Jacques Kallis.

Watson succumbed to a calf complaint ahead of this week’s first Test against South Africa in Brisbane, adding another chapter to a long history of fitness problems for the talented cricketer.

It reignited speculation Watson’s sometimes fragile frame could be best preserved as a specialist batsman, despite his obvious impact as a bowler.

However, McGrath believes selectors should keep the faith with Watson as an allrounder, saying he could rival Kallis’ impact on world cricket.

“He is two players in one,” McGrath told AAP.

“He is a wicket-taker, he is not just there to hold up one end.

“And he is a batsman. He has a great technique and is potentially one of the great allrounders.

“Look at Kallis, that is what I can see Watto getting to.”

Asked if Watson should be used as a specialist batsman, McGrath said: “I would hate to see him where he is at the stage where he is just a batsman.

“He offers so much as an allrounder. He is a quality player.”

Australian captain Michael Clarke has kept an open mind ahead of the second Test in Adelaide where Watson is expected to re-join the national squad.

“We’ll worry about that if we have to,” Clarke said.

“Shane sees himself as an allrounder. I haven’t heard any different at this stage.

“I’m pretty sure he wants to come back as an allrounder and we’ve selected him through his career as an allrounder.

“There have been games where he hasn’t been selected because he hasn’t been able to bowl.

“If he’s fit to do both, then he’ll do both. If he’s not, the selectors will sit down and work out if we’re going to select him just as a batsman.”