Pakistan have lost the series after falling 2-0 down with a match to play and Misbah was disappointed with his contribution after managing just 11 runs in total across two innings at the Melbourne Cricket Ground.
"I need to think about that because I always believe that if I could not contribute anything to the team there is no point staying there," the 42-year-old told reporters.
"There is a point where I just need to think about that even before the next game and after the series.
"In the next couple of days I will think about that because there is no point hanging around and doing nothing.
"I haven't decided (on Sydney) but let's see."
Misbah's team crumbled on the fifth day of the rain-affected test at the MCG, bowled out for 163 in their second innings in a little more than two sessions.
With his team teetering on 63 for three after lunch, he gave away his wicket after just two balls when his reckless sweep shot off spinner Nathan Lyon was caught at short fine-leg.
On a dismal tour to date, Misbah contributed only nine runs in total in the first-test defeat in Brisbane.
The veteran captain has pondered quitting for more than a year but opted to stay on to lead the team on trips to England, New Zealand and Australia.
Friday's collapse marked the second time that Pakistan have been bundled out on the final day in their last three tests.
They lost nine wickets after tea on the fifth day of the second test against New Zealand in Hamilton last month to lose that contest by 138 runs and the two-match series 2-0.
Misbah, however, missed the game at Seddon Park due to the death of his father-in-law, though he would have been unavailable for the match anyway as he needed to serve a suspension for a slow over rate.
(Additional writing by Greg Stutchbury in Wellington; Editing by John O'Brien)
