Nathan Lyon looks set to fight for his career in Sydney after rain virtually ensured the Boxing Day Test will end in a draw.
Australian captain Steve Smith has conceded it will be extremely difficult to force a result on day five at the MCG after rain again forced play to be abandoned.
The hosts were 6-465 at stumps on Thursday in reply to Pakistan's first innings total of 9 (dec)-443.
With Australia in growing need of a matchwinner to back up their quicks and help them wrap up the series, the out-of-form Lyon is set to be joined by a second spinner for the third Test at the SCG.
"It's been spinning quite a lot there in Shield cricket this year, so there's a good chance there'll be a spinner added, I daresay," Smith said on Thursday.
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Smith would not say who was under consideration for Sydney, although Steve O'Keefe is considered the most likely.
The skipper said it was up to selectors whether Lyon kept his spot after taking 1-115 at the MCG.
"He obviously hasn't bowled at his best in the last couple," Smith said.
"It's never easy bowling against subcontinent players when the ball isn't doing a lot off the wicket as well.
"I guess we're looking for Nathan to just be a little bit more consistent in the way he bowls."
While Lyon has earned his status as one of Australia's greatest offspinners, his poor form means he is no certainty to be selected for February's tour of India.
Smith (100no) had just brought up his 17th Test century when play was halted at the MCG shortly before tea on Thursday, with the dark clouds above soon producing thunder, lightning and a heavy downpour.
Smith's hard-fought century proved to be a saving grace for the hosts after middle-order duo Nic Maddinson and Matthew Wade again failed with the bat.
Maddinson, who was clean-bowled by Yasir Shah for 22, now seems certain to lose his spot at No.6 after scoring zero, one and four in his previous two Tests.
And wicketkeeper Wade, who was dismissed for nine, is also under pressure, considering he was selected ahead of Peter Nevill for his batting rather than his keeping.
There was drama during Wade's short-lived dig when Pakistan's double-century maker Azhar Ali copped a nasty blow to the helmet while fielding at short leg.
Azhar crumpled after being struck at full force but was eventually able to get to his feet and walk from the ground.
Usman Khawaja earlier fell agonisingly close to his sixth Test century, dismissed on 97 by Wahab Riaz in the fifth over, before Peter Handscomb made 54 to continue his strong start to his Test career.
Left-arm quick Wahab was the most threatening of the Pakistan bowlers, taking 2-135, while Sohail took 2-86.
More showers are forecast for Melbourne on Friday but the conditions are expected to clear up later in the day.
