There's no way to know, that for sure. He was tipping pitches his last few starts and it's not like he doesn't get emotional and rocked from time to time. All starters so far have been knocked around, fair to guess Stras would have been too.
Also, is Stras going to make up that run differential on offense as well? I know he's a good hitter and all, but I don't see him bringing in all those stranded base runners. I don't see him getting everyone not named Desmond and Zimmerman hitting.
Strasburg is the best pitcher in your rotation... How does it not change things? Substituting him for Det makes a big difference.