Pravit was arrested hours after tweeting: "Freedom can't be maintained if we're not willing to defend it." He had been detained once before, shortly after the coup.
Upon his release on Tuesday, he tweeted: "My ideology is intact."
But on Wednesday he said that he had taken the decision to resign from the English language newspaper after talks with management.
Since the May 2014 coup, numerous politicians, journalists and citizens have been required to attend "attitude adjustment" sessions.
These sessions are essentially brief periods of incarceration by the military and can last up to a week.
Last week, the military detained two former MPs who had been critical of the junta, including a former energy minister.
In addition to the adjustment sessions the military have also increased prosecutions under the country's lese majeste legislation, which prohibits any criticism of the monarchy.