The Democrat Party is attempting to rein in Bangkok governor MR Sukhumbhand Paribatra's "maverick" governing style.
Party bosses have told him they are willing to field him as a candidate for re-election next year only on condition that he is more accountable to the party and listens to its advice, sources say.
Democrat and opposition leader Abhisit Vejjajiva officially announced MR Sukhumbhand as the Democrats' candidate Friday.
Mr Abhisit admitted MR Sukhumbhand had been criticised for working independently from the party but he said that was because the party gave the governor administrative freedom.
He insisted the governor had worked with honesty and devotion.
The party's executive board nominated MR Sukhumbhand as its choice on Thursday, but the decision was far from unanimous.
He received nine votes from the 19-member committee, against six votes which went to deputy leader Korn Chatikavanij.
Party sources said the executives preferred Mr Korn to run in the election but the deputy leader agreed to put himself forward too late.
By that time, the party's heavyweight Suthep Thaugsuban had already thrown his support behind MR Sukhumbhand.
The party's support for MR Sukhumbhand hinges on a condition that he must not maintain the "maverick" style of working seen in the past.
The party wants to keep the seats of its Bangkok MPs and is worried MR Sukhumbhand's independent style of governing could upset their chances.
The party will decide on MR Sukhumbhand's policies and administration team, including who will be selected as deputy governor candidates and advisers to the governor, so the party is ensured of its presence in the way the city is run, the sources said.
Key Democrat leaders are aware MR Sukhumbhand will be attacked on the delayed construction of the Bangkok Futsal Arena in Nong Chok district, his performance during last year's flood crisis, and the BTS extension investigation.
Presenting the candidate, Mr Abhisit said MR Sukhumbhand understood the city's problems and knew how it ran.
The capital needs an uninterrupted management and governor who knows its problems, he said.
MR Sukhumbhand was unlikely to bring political conflicts into the capital's management.
However, Mr Abhisit did note that if MR Sukhumbhand wins the election, he would have to cooperate more with the Democrat Party.
The party has changed a regulation to require its members responsible for local administration to be more accountable to its wishes.
MR Sukhumbhand said the Bangkok governor's job is demanding and complicated.
A new governor would need time to learn, but if he were re-elected he would be able to carry on where he left off, to improve on the work he had done in the past four years.
He promised to tackle traffic, environmental and safety problems more earnestly. He has yet to choose an auspicious day to leave his governor's seat, he said.
Prompong Nopparit, spokesman of the ruling Pheu Thai Party, said the Democrat Party picked MR Sukhumbhand to solve its internal conflicts rather than the public's problems.
He said the Pheu Thai Party would introduce its Bangkok governor candidate by Jan 10.
Mr Prompong said Pol Gen Pongsapat Pongcharoen, widely tipped as likely to get Pheu Thai's nod, was an interesting choice.