Watson was brought home early from the Champions League Twenty20 in South Africa last month amid fears of burnout.
Talismanic allrounder Shane Watson has become Australia's latest injury scare ahead of next week's Test against South Africa after pulling up with a sore calf during a Sheffield Shield clash.
Watson left the field after bowling his first over of the day for New South Wales in their match with Queensland in Brisbane on Saturday.
On Friday, former Test skipper Ricky Ponting was withdrawn from Tasmania's Shield match against South Australia with hamstring soreness, while pace hope Pat Cummins was ruled out for the season with a stress back complaint.
Watson, 31, stopped short after bowling his sixth ball and then held a lengthy conversation with New South Wales and Test captain Michael Clarke.
He stayed on the field for the following over but later left the ground to return to his team's dressing room.
Medical staff reported Watson suffered calf soreness and would continue to be assessed during the second day's play.
Australia's vice-captain has had problems with his troublesome calf in the past five months and was sent home from England during the one-day series loss in July.
Watson was brought home early from the Champions League Twenty20 in South Africa last month amid fears of burnout and a lack of activity in the longer form of the game.
Cricket Australia's plan was to give Watson a rest and have a four-day Sheffield Shield game for New South Wales, before tackling South Africa in the opening Brisbane Test.
The first Test between Australia and South Africa begins in Brisbane on Friday. – Sapa-AFP