Why can't Khedira be relied upon?
It looks to me like the idea is to rely upon him as a midfield starter this year. Before his injury troubles, he played 4-5 seasons of 3000+ minutes. Then major injury, and niggling little minor injuries followed as he tried to recover and regain full fitness. But he upped his minutes from 650 in 2014-15 to 1950 minutes last season for us. Add to that Allegri seemed fine playing the full 90 minutes in both of the first 2 matches this year... which was rarely done last year, I think he had maybe a half-dozen appearances all last year where he played the full 90...
I'd say Allegri and our management are counting on Khedira to be healthy and a starter this season... They've invested a lot in returning him to fitness, and are counting on having succeeded.
It's a little worrisome to rely on him, but I'm betting on Sami having a huge year for us.