Quinn won’t be running a 34… it’ll be a 43 under, which looks like a 34 to the average fan.
The DE’s in the 43 under don’t need to be as big as a 34 DE. One DE is a LEO, which doesn’t even have to be as big as a normal 43 DE, mainly because of his alignment (9). The other DE, called a Big End much of the time in the 43 under, needs to be somewhat bigger than a regular 43 strong side DE… but not as big as a 34 end. They must be strong against the run, which Lawrence is.
Having said all of that, it is a good question where exactly Lawrence will be used. They could use him as a LEO some but he is at the upper end of the size scale for that position. Gregory is pretty much a textbook example of a LEO and should spend his time there. Lawrence could be used to spell Gregory at times there though.
He will probably be used at Big End a good portion of the time (when in the 43 under) because he provides a good pass rush while also being solid against the run. but that is speculation.
The big end will and can line up anywhere from the 5, down to the 4 and even the 4i, which is inside the OT. I would imagine if they are in the 43 under and they think it could be a pass, then Lawrence would play Big End as a 5. In running situations, they’ll probably use a guy like Urban or Watkins in the 4 or 4i to better shut down the OT/OG bubble. It’ll depend on the situation.
Of course, in the nickel, which will be an estimated 60-70% of the time according to Quinn… they will really be in a 4 man line and Lawrence will be playing the SDE that he’s been playing for years, so he’ll just be playing like normal for him.
Perhaps in some heavy defensive sets they’ll put Lawrence at LEO and Urban at Big End to better stop the run. That may or may not happen. But again the base 43 under will only be 30-40% of the time.
DeMarcus might even go inside and rush from the 3 as a DT. Quinn will use two 3’s in some pass rush sets.
Ultimately, we will just have to wait and see what Quinn does with Lawrence, but I’d expect something along the lines of what I just described. There’s a lot of ways to use him.