Sport First is losing editor James Eastham, who has been at the paper since he joined as a trainee in 2000.
Eastham, who was made editor last year, is to freelance. He refused to comment on speculation that he is to be involved in a new sports magazine. The paper said it hoped to find a replacement in time for the start of the new football season.
Eastham has twice been nominated for Young Journalist of the Year in the British Press Awards.
Meanwhile, Sport First proprietor Keith Young is flying to Singapore this weekend to meet Lyn Holloway, former chief executive of the South China Morning Post, who is now with The Shanghai Daily. The pair are in advanced talks for Sport First to provide the English-language daily, which sells around 50,000 copies, with sports coverage.