Graham Coughlan has left Bristol Rovers and is expected to be announced as the new manager of Mansfield.
Rovers "reluctantly" gave Mansfield permission to discuss the vacancy with Coughlan on Monday, after rejecting their approaches twice since the departure of John Dempster on Saturday.
Mansfield are 18th in League Two, seven points above the relegation zone having not recorded a victory in their last five league fixtures, whereas Rovers sit fourth in League One.
Rovers chief executive Martyn Starnes told BBC Points West on Tuesday: "He's departed from us and we expect him to be confirmed at Mansfield later today.
"We are already on the road to looking at a replacement manager. Ideally I'd like to make an appointment by the weekend, but I think that's unlikely."
Rovers face Plymouth on Tuesday night in a replay of their second-round FA Cup tie, while Mansfield host Northampton on Saturday.