Quoted for truth. If a player is going to get hurt, it can happen anywhere at any time.
Exactly, this is just poor luck coupled with an environment that is perfect for injuries.
He rotated as much as he could:
LB: rotated in the form Tsimikas (got injured)
LCB: rotated in the form of Rhys
RCB: played fab 45 mins before playing Koumetio (u-23 kid)
RB: Trent played the 90 minutes to regain fitness
CDM: Rotated in the form of Clarkson (u-23 kid)
RCM: Keita playing to regain fitness and subbed off
LCM: Minamino played in there because we had nobody else other than regulars (Henderson, Wijnaldum, and Jones)
LW: Jota was supposed to act as rotation because other than him, there was only Origi who is not a starter who could play and he was already playing
ST: rotated in the form of Origi
RW: Salah because there was no one left to play other than regulars
Edit:
This is the list of players that were available (on the bench) once that heavily rotated starting XI was fielded: Adrian, Jarosz (GK), Matip, Koumetio,Robbo,Neco, Hendo, Jones, Gini, Jake Cain, Sadio, Bobby
If you factor in that Trent and Keita were playing for match fitness, I don't see which regular he could've rested he did not rest in one way or the other. Short from fielding the whole u-23 team and getting a sh*t ton of criticism (probably from the same people), I don't see what he does to avoid. Poor luck and a particularly agressive Midtjylland team for a game that had nothing significant attached to it, that's all.