Ri, who was the army's No. 3 man, appeared to have been demoted. He was mentioned in a report published in North Korea's state newspaper Rodong Sinmun.
In the message issued Tuesday that included results from the Seventh Party Congress, a list of Politburo members included Ri's name – 10th in a roster of senior North Korean officials.
Ri was the North Korea equivalent of chairman of the joint chiefs of staff prior to the demotion, South Korean newspaper Donga Ilbo reported.
Since fully assuming power in 2012, Kim has ordered the execution of his uncle-in-law Jang Sung Taek in 2013, and likely executed his defense minister, Hyon Yong Chol, in 2015.
Ri was appointed army chief in 2013, but was missing from state events celebrating the Lunar New Year and the Feb. 6 satellite launch, although Korean People's Army Vice Marshal Hwang Pyong So and top politician Pak Yong Sik had been present at the events.
The demotion and return to office could mean Ri had been purged then rehabilitated, according to a source at Seoul's unification ministry.
Ri could still be out of favor with Kim, however.
"The fact that Ri's name was 10th on the list issued by the Central Committee of the army is a sign that he has fallen in the ranks," the unidentified source said.
It's likely Ri had spent some time at a prison camp, the source added.
Since Kim assumed power, the North Korean leader has purged three out of four chiefs of staff.