quoted for juicy part

Singer informed Empire Magazine (via CBM) likewise that the thought process for how to best present the character has been ongoing since the project’s beginning:

“Quicksilver was always in our script. Marvel were informed early on that I was using him. The way it’ll play out in our movie versus what I believe they are going to do [ in 'The Avengers' sequel] is so different. And this is not an enormous role – he’s only on one beat of the movie.”

source

http://screenrant.com/x-men-days-future-past-quicksilver-boliver-trask-peter-dinklage/