I am not a fan of changing in-game defenders when our gameplan is to defend 0-0 unless one of the players gets injured and the change is inevitable. The newly fielded defender needs time until he gets tuned up with the whole defending system and that's a big risk given how the pressure mounts towards the end, especially in a CL game at Kamp Nou against Barca. We had been losing points because of that under Spalletti (remember 2-3 with Santon coming on), we have been losing points under Inzaghi too. In the last match against Barca, I was sitting and praying for Inzaghi not to sub off any of the defenders. Acerbi for De Vrij was a forced sub because of the injury and the former didn't disappoint, but when Dumfries came on I was afraid of looking at my laptop screen honestly. With each Barca attack I was biting my nails and expecting some fuck up from defenders which eventually happened. Happened because of the substitute ffs. Thank God, and VAR for ruling out the potential penalty call albeit controversial.
I hope Inzaghi approaches the substitutions like Conte in this particular match. If our aim is to park the bus wingbacks won't be having much to do in attack, hence shouldn't be getting exhausted in 90 mins.