His injury problems started in Australia during the 2010-11 Ashes series.
Hoping that Broad would not have to contemplate over choosing one format, Miller said: "At this moment of time we're not thinking about taking him out of a format because he's got that sort of quality, but if we reached the stage where his body wasn't responding to all kinds of cricket then we're open to that.
"What we have to do is react to the injury that he has at any one time. He felt, and we felt, that he had to look after his body so he went away and worked really hard at that. Since then there have been a few niggling injuries, but anybody can get them," he insisted.
Even though Broad finished 2012 as the fourth-highest Test wicket-taker among fast bowlers, with 40 wickets at 31.70, his form deserted him in the second half of the year against South Africa and India.
His injury problems started in Australia during the 2010-11 Ashes series, when a strained stomach muscle sustained in Adelaide forced to return home early. He then suffered a rib injury during the World Cup followed by a shoulder injury late in the 2011 home season.