Insiders in K Chandrashekar Rao's TRS said Vishweswar Reddy was upset with its senior leaders.
A lawmaker from Telangana's ruling party has quit amid buzz that he is heading for the Congress. With weeks to go for assembly elections in the state, the resignation of K Vishweswar Reddy is seen as a deep setback for the K Chandrashekar Rao's Telangana Rashtra Samithi, which is seeking a second term in power.
Assembly elections — initially scheduled for next year — will be held in the state on December 7.
Sources said the parliamentarian from Ranga Reddy district's Chevalla is likely to join the Congress when Sonia Gandhi visits the state later this month.
Vishweswar Reddy belongs to what is considered the politically influential Reddy community and analysts say it could influence the vote in at least a few constituencies.
An engineer-turned-politician, Mr Reddy joined the Telangana Rashtra Samithi in 2013. His grandfather Konda Venkata Ranga Reddy was a freedom fighter who became the Deputy Chief Minister of Andhra Pradesh. The Ranga Reddy district is said to have been named after him.
Party insiders said Mr Reddy was upset with its senior leaders as he felt he was not given due importance. In a three-page letter to party chief and Chief Minister K Chandrasekhar Rao today, Mr Reddy spoke of ideological reasons that added up to deep criticism of the party.
Amid the deep rift, there were reports that Revanth Reddy, the working president of the state Congress, had challenged KCR, as the Chief Minister is popularly known, to stop Mr Reddy from quitting.
There was speculation that another lawmaker, Seetharam Naik, would also quit. At a press conference held soon after, both lawmakers had denied any such possibility.
Assembly elections were due in Telangana next year, but the Chief Minister pushed for early elections in hopes of keeping his voter base together ahead of next year's general elections. Opinion polls say his move could pay off, with his TRS emerging as the big winner, leaving both Congress and the BJP far behind.
Currently the party has 63 seats in the 117-member assembly, the Congress had 22 and the BJP, 9.