Found this little tidbit in the latest Spads article
Johnson has some options, for sure. He admits that using more of a 3-4 look is "in the back of our minds," depending on what the team does on first and second down. Johnson remains committed to stopping the big play first, but he also recognizes that the run defense made tremendous strides last season and that Patterson and Bunkley are emerging as one of the best young tandems in the league. The linebackers are all young, fast, physical and intelligent. The secondary has a bunch of good cover men.
We saw a little bit of this against the Patriots and it worked quite well. The Eagles certainly have the personnel to run the 3-4 in certain situations. They don't have the big 2 gap nose tackle to run it all the time, but on passing downs I could absolutely see the likes of Gocong, Clemons, Cole, and even Smith rushing from a standup LB position.
It also presents a potential nightmare for opposing offensive coordinators having to prepare for a team that can show you a 4-3 or 3-4 look on any given play.