A DUP MLA who is understood to have backed Edwin Poots in the party's leadership battle earlier this year is stepping down from the assembly.
North Belfast representative William Humphrey has cited personal reasons for not seeking re-election at next year's Stormont poll.
Along with his party's deputy leader Paula Bradley, the former councillor is one of two DUP MLAs in the constituency.
It has been speculated that former Belfast mayor Brian Kingston and Antrim and Newtownabbey councillor Philip Brett, a one-time adviser to Nigel Dodds, are among the front runners to be selected as the DUP candidate alongside Ms Bradley.
The Belfast Telegraph reported that both men, who are friends and keen supporters of the Northern Ireland football team, had put their names forward for selection.
Mr Brett (30) is the brother of Gavin Brett, who was 18 when he was shot dead by the UDA in 2001 as he chatted to Catholic friends at the gates of St Edna’s GAA club in Glengormley.
Mr Humphrey first joined the assembly in 2010 when he was co-opted to replace Mr Dodds.
The 54-year-old is currently chair of the assembly's Public Accounts Committee.
A DUP statement said: “The North Belfast assembly candidate selection is an internal matter and an announcement will be made in due course.”
Slugger O'Toole deputy editor David McCann said the DUP needed "transfer friendly" candidates in a constituency where the unionist vote has been declining.
"Humphrey leaving creates some space for a party like the TUV," he said.
"Bradley and Brett would be considered on the liberal side of the DUP. Having said that, that electoral demographic is shrinking in North Belfast – unionist vote has fallen every year since 2001."
