I took a second look at Spriggs pass blocking against Mack in the first half, and a first look at the second half.
I observed earlier in the game thread that I didn't understand why Spriggs was taking a 3-point stance on passing downs, especially against a guy like Mack. Upon further review, thanks to one replay from an end zone view, Spriggs was in a 2-point stance on at least one play and probably more if not all passing downs. At the same he wasn't taking that 1/2 step deeper set typical of LTs.
From the standard sideline shot when the Packers were moving left to right his 2-point and 3-point sets were indistinguishable.
This may be the first instance in the McCarthy era where an O-Lineman played with too low of a pad level. That's a lot of travel for a 6'6" guy to get in proper position with good balance especially against a guy with elite burst. The inclination is to stand up, going from too low to too high, getting off balance, losing fluidity and being unable to deliver a good punch. Besides Mack, it can also make lesser players look better than they are.
Perhaps this is some kind of overcompensation for being coached away from too high a pad level, but it's something that requires adjustment.