A senior official commanding the TA battalion told on condition of anonymity that feelers have been send by the 48-year-old actor, saying that he is interested in joining up.
"The biggest impediment is that the upper age limit for entry into the battalion is 42 and after that if anyone has to be included, it has to be referred at the highest level, which is a tough ask, " said the official.
Recently, former India Cricket team captain Kapil Dev was inducted into the Territorial Army after it was cleared at the highest level.
"Veteran theatre and film personality Nana Patekar's application for entry into the battalion is still being considered, " said the official.
Mohanlal had his first major role as an army officer in the movie "Keerthi Chakra". Released in 2006, the film was directed by Major Ravi, a former commando with the National Security Guards (NSG).
In August 1991, Ravi headed the team that shot dead Sivarasan, the mastermind behind the killing of former Indian prime minister Rajiv Gandhi.
He quit the army due to his passion for movies.
Ravi, who also directed the superstar in "Kurukshetra", confirmed that Mohanlal is interested in joining the Territorial Army.
"Yesterday only we discussed this and he is very keen. He is now getting his papers ready to be sent for processing. It was after the role he played as a Major in 'Keerthi Chakra' and Lt. Col. in 'Kurukshetra' that he became really interested, " said Ravi.
The superstar was not available for his comment.