Speculation in Westminster that the former foreign secretary may be preparing the way for a return to frontline politics was reignited when he made a barnstorming speech attacking the Government's "rancid" policy on benefit cuts.
The elder brother's address in the Commons echoed criticisms made by the Labour leader, who accused David Cameron of pursuing a "divide and rule strategy" by trying to pitch low-paid workers against the unemployed.
Westminster rumours have suggested that David Miliband may have his eye on the job of shadow chancellor, and Ed Miliband declined to guarantee that Ed Balls would keep the post up to the 2015 general election.
He said that time had healed some of the bruises from the 2010 leadership election in which he defeated David by a wafer-thin margin, but told the Daily Mirror that this should not be seen as an indication that his brother was about to join the shadow cabinet.
Ed has always said he would like to have his brother in his top team, while David has made clear over the past two-and-a-half years that he wants to stay away from the front line.
Speaking to the Mirror, Ed Miliband said: "Of course it was a bruising leadership contest and as time goes on that sort of recedes and that's good for our relationship.
"But I wouldn't take it as indication about a change in his view he's not coming back to the shadow cabinet, but the door is open."
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Asked if Balls was guaranteed to hold the shadow chancellor's post up to the election, Miliband said: "I have the same rule for everybody across the shadow cabinet. And it's a very principled position.
"I am going to do nothing that's about measuring the curtains. It's the measuring the curtains thing - you start naming your Cabinet two and a half years before the election? Honestly.
"I think Ed Balls is doing a great job but I am not going to get into that."
Miliband revealed that he and David had a family get-together during the Christmas break.
He and Justine gave David and wife Louise some wine "and other gifts". David gave him a book on the Boston Red Sox.