he's not an outsider. these aren't bad players per definition, and all of them would start for the majority of our league opponents, udinese included. they beat us with inferior players, with better motivation and better physical shape.
for example, rugani completely lacks match fitness (even sarri himself admitted that it's his own fault), and while playing both de ligt and bonucci until they're dead, rugani is fine physically, terrible in his confidence. people management for dummies, chapter one: empowering your employees. imagine this: we're leading 3-0 against lecce or bologna, match is already won, sarri already knows the schedule and the recovery times for both chiellini and demiral, yet he keeps both de ligt and bonucci on the pitch. double blow: rugani loses confidence, the other two get too tired (see bonucci's dumb mistakes lately). that's not how you manage your players. he did the same at napoli, playing the very same 13-14 guys, and letting the others rot at the bench.
there's muratore he referred to as one of our u23 players ready for big time football. how many seconds did he use him, when all we needed was some fresh legs? how come that other teams rely on youngsters to keep the starters fresh as possible, but we simply aren't?
sarri used all of his 5 subs on 3/11 occasions so far. 3 subs yesterday, when all we needed was someone to run along with those toothless udinese attacks. just tell me with a straight face that it's completely fine.
as for tactical preparation, this is such a naive, predictable, one trick pony kind of team. you don't defend at 45-50 meters when you're prone to allowing counters, don't have proper dm's for your game and have no fresh legs at all. teams supposed to have an alternative style (a tactical approach and/or a formation) for special situations. and the worst of them all: we simply can't defend a lead.
this is not a perfect squad, it's been obvious from day 1, and this post-lockdown period has been crazy and unpredictable for many teams. not everything is sarri's fault. but he's been making tactical, man management, game management, rotation mistakes without changing his routine. he's just too stubborn to realize when and where he should change something. he's not a bad coach like delneri or ferrara were, but as a one trick pony lacking any flexibility on both human and tactical level, he's an awkward fit for juventus.