It's interesting to see how people are reacting to this. Obviously no team has another 3 or 4 win starter that can just jump in to replace that kind of production, but honestly for the Jays this is far from the worst injury that could happen. We will probably lose 1-3 wins, but like it was pointed out by a few people, the replacement for Stroman (Norris or Estrada) should still put up 1 or possibly 2 wins.
Imagine if it was Donaldson. That could be up to a 7 win swing, when you consider that his replacement would be someone like Goins, Kawasaki, or Tolleson (with the replacement playing either 3B or 2B) putting up replacement level numbers.
Obviously it sucks huge donkey dick (or goat depending on your preference,) but if we had to pick one position to suffer an injury, a SP could be the easiest loss to absorb.