Sydney, Jan 3 (IANS): Australia's pace spearhead Mitchell Johnson is doubtful for the fourth Test against India at the Sydney Cricket Ground (SCG) starting Tuesday after missing training Saturday due to hamstring soreness.

Johnson has been the home team's most worked bowler in the first three Tests of the four-match series, reports The Sydney Morning Herald.

Australia have two back-up pace bowlers in their 14-man squad for fourth Test here with Mitchell Starc likely to take his place if Johnson becomes unavailable.

"It depends on the fitness levels of other blokes and how they pulled up from last week," Starc was quoted as saying by the Sydney Morning Herald Saturday.

"I'll always prepare to play, and I feel like the ball's coming out well from the last two BBL games, I'll keep doing the same and preparing to go."

Johnson had earlier said that pacers would need a break after the Sydney Test following four back-to-back matches.

"Definitely, all us bowlers feel like we need to have a bit of a freshen up," Johnson said. "So we'll just see what happens after this match here," he said Friday.

"And then we've got some tri-series One-Dayers (against India and England), so hopefully I can get a bit of a break at some stage there. I had a break after the one-dayers in Perth earlier [in the season], which was to freshen me up and that was really helpful."

Johnson also spoke of his preference for bowling shorter spells due to 'batting friendly' wickets produced in Adelaide, Brisbane and Melbourne, noting that the pacers were forced into bowling longer spells against India.