Prime Minister Prayut Chan-o-cha made remarks on Tuesday suggesting he sees little opportunity for him returning to power for another term.
Prayut was responding to reporters' questions about his political plans as the bloc led by the Move Forward Party works to form a new coalition government.
He seemed amused when reporters asked about the possibility of smaller parties nominating him as prime minister if the MFP or Pheu Thai fail to put together a coalition government.
Asked about the coalition, Gen Prayut -- of the UTN Party -- said he was not involved.
Bhumjaithai leader Anutin Charnvirakul said on Tuesday he never held talks or had any agreement with ousted former prime minister Thaksin Shinawatra amid rumours of a "secret deal".
He said his recent meeting with one of Pheu Thai's three prime ministerial candidates at a football match in the UK had nothing to do with politics.
A photo of the pair circulated last week after former massage parlour tycoon Chuvit Kamolvisit made a Facebook post about their allegedly secret negotiations if the MFP failed to gather more than half of the House seats required to form a government. According to Mr Chuvit, the secret deal was called "come home", a reference to Thaksin, who recently announced his intention to return to Thailand next month.
Mr Anutin declined to discuss the prospect of a rival coalition.