Sure, it could be a lack of hydration. It could also be over hydration, improper diet, improper rest/sleep, muscle imbalances, joint instabilities, bad motor patterns, freak accidents etc. Really no way of knowing from this side of the field. This is a professional football organization that specializes in athletic performance among other things. I have faith that Steve, Oz and Harbs do their utmost to optimize the performance and health of their athletes. Be it hiring the most qualified personel available to making sure the players drink water. I have a hard time believing players just swishing and spitting for a 3-hour practice - but then again I haven't had the opportunity to attend TC. Injuries are as much a part of football as TD's and INT's.