Does Colossus work for edge rushers?

I’ve been sticking them in the middle at DT over the course of the year however, with the influx of Colossus D Linemen, I now have 3 D linemen with Colossus on my team. 

With a 4 man d front it’s amazing 

However, when running dime the edge rushers with colossus don’t really do much. Especially compared to Barno & hunter UF lit up who used to come screaming off the edge every play. 

Does Colossus ONLY work when the player is  Double teamed?