The Essex batsman was named in the squad on Friday and will be hoping to make an impact in the ODI series against New Zealand before the tournament, which begins in June.
Miller believes that Bopara can still find his best form in an England shirt despite having been dropped for the winter tours of India and New Zealand.
"He's been given another opportunity because we know what he is capable of doing. He's got all aspects to his game," he told Sky Sports News.
"There's the bowling, which has come on very, very well. Batting-wise we know what he is capable of doing and he's good in the field too.
"He adds strength to the squad. But it's not just about one person performing - it's about the whole squad."
Bopara hasn't played for England since the World Twenty20 tournament last autumn.