A former winner of the tournament, Scott's best return in seven PGA appearances this year came at the Honda Classic when he tied for 13th in a season where he has paid the price for inconsistency on the greens.
Aaron Baddeley and Rod Pampling are the best-performed Australians after carding 71 and 70 respectively to sit in a share of 25th.
They are seven shots behind Zach Johnson and Ryan Moore who lead at nine-under par.
Baddeley and Pampling will be joined at the weekend by John Senden as the only Australians to make the cut.
Two-time champion Johnson shot a brilliant second-round 65.
He carded four successive birdies, a six and an eagle in total, in a seven- under-par round that matched Scotland's Martin Laird for the best of the day.
That left Johnson alongside fellow United States Ryder Cup player Moore at the top of the leaderboard.
"Keep hitting fairways and keep putting myself in position to be aggressive," the 42-year-old said when asked what he will need to do to win the tournament.
"I don't want to take my foot off the pedal because what I've learned certainly over the last so many odd years with these young guys is there's no fear.
"They are going full bore so there's no reason I shouldn't either," the two- times major champion said.
Moore had five birdies in a blemish-free 67.
Sergio Garcia had a club-slinging meltdown on the 15th, hurling his driver into bushes during another troubled round.
Returning to the tournament for the first time in eight years and after a disappointing title defence at the Masters, the Spaniard also missed the cut after finishing with 72.
It was the first time since 2010 that Garcia missed the cut in successive starts.
That was the PGA Championship and, 10 weeks later, the Castello Masters in Spain.
This time, he missed the cut in the Masters and Texas Open two weeks apart.
AAP
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