I understand the risks involved with putting a guy with limited experience above AA into a big league rotation. Trust me, I've been following this guy long enough to tell you that while he has a world of potential, he still needs to do some important things such as build up endurance and face more advanced hitters. However, at the moment, the alternatives are not looking all that great. We've seen the results of Spring Training games, yes, but there are also workouts and drills. The coaching staff has been monitoring Guzman, Williams, Hill, and Marshall a great deal. They know their jobs are on the line and aren't going to take any stupid risks. Right now, Marshall has performed better than any of those guys. He wasn't handed the #4 slot blindly. If they think he's the best option, then I think there's something to be said for giving them the benefit of the doubt in a rough situation like this.