Pure speculation but I think Mathews is suffering from Norovirus as there appears to be a significant outbreak in Toronto.
https://toronto.ctvnews.ca/norovirus...nada-1.6863382
I have had this before and let me tell you, it's not remotely fun. The level of fluid and food that leaves your body in a violent fashion is jaw dropping. You wonder if your going to make it and wonder where all this fluid and solid food is coming from because you haven't consumed it.
If you are not on top of your electrolytes and hydration, it can lead to hospitalization and more. Pure speculation but I can see the Dr's pulling him for fear of a cardiac event due to physical demands and stress on the body.