The other assumption here is that he plugs and plays when he gets back as the exact same pitcher, right? It sounds like he has NEVER had a similar injury. All pitchers get their power from their legs and this is not a big guy at all.
I think this is a much bigger deal than people think. You lose your top 2 pitchers it does not mean you just compare them to the replacement pitcher. You also put more stress on the bullpen because you are getting less innings from your starter. You also can’t position your 1-5 the same when you have off days and series coming up.