The Serbian, who completed back-to-back outings against Wigan and Galatasaray earlier this week, was left out of the Reds' 18-man squad for the 2-1 triumph.
So soon after returning from anterior cruciate ligament damage, Sir Alex practiced prudence when Vidic subsequently felt tightness in his knee ahead of Sunday's game.
"He was just feeling a bit tight round about his knee and we decided just to give him a break today," the boss told MUTV. "Hopefully he'll be alright next week."
The Serbian may be in contention to face Tottenham at Old Trafford next Saturday, a timely boon for the Reds after Rio Ferdinand limped through much of the win over Liverpool.