Deputy SNP leader Keith Brown said it’s “very difficult” to see how disgraced Derek Mackay can stay in the Scottish Parliament.
Brown said colleagues were shocked by Mackay's after it emerged he’d bombarded a 16-year-old boy with texts and called him “cute”.
Mackay, who was finance secretary, quit his government job on Wednesday night after an he was confronted by SNP leader Nicola Sturgeon. The 42-year-old was then suspended from the party.
But he remains an MSP and has not revealed whether he will bow to pressure and give up his constituency seat.
On the BBC’s Politics Scotland, Brown was asked if he can possibly cling on.
Brown said: “I think it's very difficult to see how he can continue, but it is his decision."
He added: “I wasn't aware of his text habits, if you like, and this communicating with people of that age – completely unaware of that and it came as a shock to people throughout the party.
"You could see the shock on people, not just the SNP but other parties as well."
Mackay sent around 270 messages to the teen over six months, asking him to dinner and to a rugby match.
He quit as finance secretary on the eve of his Scottish budget announcement, leaving finance minister Kate Forbes to stand in.
On Friday, the Record revealed he had asked 25-year-old SNP activist Shaun Cameron for “naughty pics” after following him on social media.
