Kerry Byrne of Cold, Hard Football Facts engineered an indicator for offensive and defensive line play that he calls the "Hog Index". This stat takes into account a unit's success on third down, the negative pass plays they generate on defense or allow on offense, and yards per rush attempt (YPA).
Without peeking, one might assume a dramatic increase in these indicators with Mankins as opposed to without. Let's take a look at the numbers last year, from when Mankins was holding out and when he returned to the line:
| ||Rank on OHI ||YPA (rank) ||NPP% (rank) ||3down (rank) ||Avg. rank
||1st ||4.20 (12th) ||6.75% (8th) ||46.43% (2nd) ||7.3
|End of Year ||1st ||4.35 (10th) ||5.64% (3rd) ||48.22% (2nd) ||5.0
While there were some notable improvements (1.11 percent decrease in negative pass plays, 1.89 percent increase in third down conversions), it's not the astronomical improvement many might suspect would take place with the addition of a Pro Bowl guard.
Overall, the Patriots were first in the league in the Offensive Hog Index both before and after Mankins' seven-week holdout.
Byrne points out that while Mankins may have helped the unit, some of those numbers should be attributed at least in part to "the otherworldly play of Tom Brady".
"[T]he big improvement after the Mankins return came in Negative Pass Play percentage. But was that because of Mankins, or because of the other-worldly play of Tom Brady? The QB had thrown all four of his regular-season INTs by the time of the Baltimore game in Week 6, with Mankins still out.
Was the great guard responsible for the fact that Brady did not throw another pick the rest of the year? We don't know. But it'd be a stretch to say it was."
It may seem like sacrilege to suggest that the Pro Bowl guard is an unneccesary component to the success of the Patriots offense. It bears mentioning, though, that the Patriots offense did just fine without him.