Rovers have confirmed talks are in progress with the 30-year-old midfielder, who will be out of contract in the summer.
Williams told the Lancashire Telegraph: "It has all been very positive. Both parties want the deal to happen and negotiations are still ongoing."
Dunn is due to face Aston Villa in the Carling Cup semi-final first leg on Thursday after returning from a calf injury in the 4-1 defeat to Manchester City on Monday.
Source: PA
Source: PA