By Alek Arend The Dallas Cowboys are going to be without franchise quarterback Dak Prescott for the next six to eight weeks. Prescott suffered a significant injury in the team’s season opener Sunday night. Now, the big question is what will the Cowboys do at quarterback? Some have suggested the Cowboys should go after Jimmy Garoppolo or maybe even Cam Newton. Believe it or not, even Colin Kaepernick’s name has been thrown into the mix. However, it doesn’t appear Mike McCarthy is heading in any of those directions. The Cowboys have officially named Cooper Rush, Prescott’s backup, the starting q…