The Chief Secretary to the Treasury said it was “unlikely” that Labour, the Liberal Democrats and the Conservatives would come to an agreement on the details of a package of further powers before the September vote.
Speaking on BBC Radio Scotland, he said: “I think what is in common is that there is now a clear commitment from all three parties to significant further devolution, particularly on tax-raising powers, so that the Scottish Parliament has much more responsibility for raising the money it spends.
“I think that is a powerful step. I think it is unlikely that there will be a completely common platform between the three parties before the referendum, but I’m sure there is the possibility of having people signed up to a common process to get there.”
He added: “I think that what we have to do, of course, is resolve the issue of independence in the referendum, but with absolute clarity that ... as it were, this isn’t a choice between independence and the status quo, this is a choice between two futures for Scotland - a future of more power within the United Kingdom or all the risks and uncertainties and dangers of independence.”
The Conservatives published the findings of their commission on further devolution earlier this month, which recommended the Scottish Parliament should have full control over income tax.
Labour has pledged to give MSPs the power to vary tax rates by up to 15p in the pound, giving Scotland control of three-quarters of the 20p basic rate of income tax, among other powers.
The Lib Dems want Holyrood to raise half of the money it spends and have control over income, capital gains and inheritance tax.