Sources close to both the Shinawatras and the military have told the Nikkei Asian Review that she is now outside the country, possibly in Singapore.
When asked whether Yingluck was still in Thailand the lawyer replied: "I don't know".
Protests and court cases have hacked at their governments and finances, while another coup toppled Ms Yingluck in 2014.
The bungled scheme became a lightning rod for anger among protesters and also saw her fall under the glare of anti-graft officials, who are still mulling whether to convict her for negligence - a charge which carries up to 10 years in prison and a life ban from politics.
Yingluck's failure to appear in court prompted the Supreme Court to hand out the arrest warrant for the former premier now faced with duty-negligence charges pertaining to the rice subsidy program implemented nationwide years ago.
The 50-year-old Shinawatra failed to appear for the verdict in a trial in which she was being accused of gross negligence and mismanagement for a 2011 rice subsidy scheme.
She is the younger sister of exiled business tycoon Thaksin Shinawatra, a highly divisive figure who was Thailand's prime minister from 2001 to 2006 when he was ousted by a military coup.
The telecoms tycoon, who once owned Manchester City football club, has not returned since and his Thai passport has been revoked.
Mr Shinawatra is believed to use a Montenegrin passport, after his Thai document was revoked, to travel between homes in Dubai, London, Hong Kong and Singapore.
This trial was indeed a strong symbolic dimension, in this country is deeply divided between pro-and anti-Shinawatra, the red Shirts against yellow Shirts, to resume the color codes used by the two camps.
Mr Thaksin remains a galvanising force for his party and a canny political operator.
"It does not help with Thailand's division and polarization", he said.
Jet Tonavanic, an associate professor at Kasetsart University, thinks Pheu Thai might now reduce its allegiance to the Shinawatra clan and build a party "that can truly earn the people's support through its fight for democracy".
And soon after taking office, she enacted a controversial rice subsidy policy: The government would buy rice from farmers, paying above market rate to boost rural incomes. It has earned $40 million from the sales but calculates the government lost billions because it couldn't export at a price commensurate with what it had paid farmers.
"I am a victim of a subtle political game", she told Thailand's Supreme Court on August 1.
Yingluck has been barred from leaving the country without court approval since 2015, when her trial started. Instead, current Prime Minister Prayut Chan-o-cha said he has "assigned officials to check the normal entry and exit routes and find out where she is".
Her lawyer Norawit Larlaeng told the court that she has vertigo and couldn't attend the hearing. The new king, Maha Vajiralongkorn, signed a new constitution in April - the nation's 20th constitution in 85 years - that entrenched the authority of the ruling generals and monarchy.
- Guardiola: Man City to rein in spending after record outlay
- Virat Kohli completes 4000 ODI runs in successful chases for India
- Ryan Giggs impressed by Henrikh Mkhitaryan's start to the new season
- Topeka optometrist explains eye damage from solar eclipse
- Trump May Terminate NAFTA, Reaffirms Plan to Build Wall
- Spieth 'essentially out' after two disappointing rounds
- Trump praises North Korea for backing down on missile threat
- Watch season 7, episode 5 Eastwatch free on Amazon Channels
- Samsung heir convicted of bribery: Company's future at stake
- Arsenal vs Leicester City