Helman claims they only kept 8 DL the past 3 seasons.
At the start of the season:
2015: 10
2016: 8 plus DLaw short term suspension.
2017: 8 plus Irving/Moore short term suspension.
The Cowboys have more good DL than they've had in a decade and them keeping 8 would be shocking to me.
DI doesn't even count for as 9 because he refused to show up to camp.
I fully expect they keep 9 and maybe 10 DL.
20-25 snap a game DL have far more value than a 4th TE, 4th RB, 6th LB, 6th WR or 9th OL.
There's also the basic issue of just talent. Some positions we simply lack it but DL is not one of them.
Also let's be honest if you have Gregory in the 8 that's a very slippery slope because we know he struggles hardcore to stay eligible. So you keep an extra guy.