The phrase "to field a candidate" means to choose and put forward a person as a candidate in an election or contest. It implies that the person will represent a particular group or party. Full definition
If the new job needs a person who is talented in a particular field the candidate should ensure that his resume shows this area as one of his areas of expertise. (resumetemplate.org)
Labour does not field candidates in Northern Ireland, and so the only nation of the UK in which the country's governing party was also the most popular party would be Wales. (theconversation.com)
The district's population is heavily religious and retired, and so conservative that Democrats did not field a candidate in the last two elections. (nytimes.com)