The Lancashire Evening Telegraph says County and Sunderland tabled improved offers for the former Welsh international yesterday.
Derby lodged an initial bid of £1.5m up front, with further payments on top based on various conditions - an offer that was also matched by Sunderland's Roy Keane, who wanted Savage to boost the Black Cats' relegation fight.
However, although both of those bids were knocked back by Rovers, Jewell then came back with an improved offer which was accepted last night.
Savage had set his heart on a move to Pride Park, rather than the Stadium of Light, because it is nearer to his Cheshire home.
The veteran is even taking a £5,000-a-week pay-cut in order to make the deal happen because he is desperate to play regular first-team football.