The only time I had a problem with being dehydrated was while I was taking chemo. Even though I was drinking plenty of water, it wasn't enough to prevent me from being dehydrated. In my case, chemo was the culprit. I had to go to the cancer center several times to get fluids via an IV.
Since Quinn is a professional athlete, he knows the importance of proper hydration. It strikes me as a bit odd that an episode of dehydration could possibly keep Quinn from playing 5 days after it happened. I'm sure he got fluids in the hospital when he was admitted and I would think that 5 days would be enough to re-hydrate and re-balance. I wonder if something else is going on.