Richard Thomson, the MP for Gordon, said he would be “astonished” if any of his colleagues tried to challenge Flynn for the job.
In a clear show of support for the Aberdeen South MP, Thomson told the BBC Flynn had the “talent and ability” to lead the group in Westminster.
It comes after it emerged last month Flynn was seeking to oust Blackford, who announced on Wednesday he was quitting the role.
Thomson said: “I haven’t seen any hard and fast numbers but I think it’s been clear that he’s been growing in stature, he is somebody who is held in very high regard by the group and I would be astonished now that there’s a vacancy to see anyone else putting their name forward.
“Of course, they’d be perfectly entitled to, they’d have every right to under our constitution and rules.
“But there is an emerging consensus, shall we say that Stephen is somebody with the talent and ability to move us forward over the next period and I think that’s who most people in the group would be looking to.”
It is understood to be the first intervention from any SNP MP on the question of who will succeed Blackford.
Flynn has not formally announced he is in the running – though it is not thought anyone else will put themselves forward.