I didn't actually test the impact of a TE blocking to prevent sacks. But, I did test the impact of having a fullback or TE blocking, versus having all players in pass patterns. I tested this across 10-12 games (564 passes) and alternated 1st half vs. 2nd half, where first half would have an extra blocker and the second half would not. Keep in mind that it was a mix of humans and SIMs I played, but I figured as long as I'm testing both equally in the same game, it would allow me to compare the percentages.
Here's what I found:
With Extra Blocker: 1.5% of passing attempts resulted in a sack; 0.3% of passes were intercepted; 61% completion % (med passes); 76% on short passes
No blockers outside of OL: 0.8% of passing attempts resulted in a sack; 0.8% of passes were intercepted; 70% completion % (med passes); 62% on short passes
So, I don't believe that the extra blocker results in more sacks, but it does create more interceptions (and likely hurries). But, the extra blocker doesn't lead to a higher completion percentage. On the contrary, completion percentage on medium passes was higher with no blockers, but lower on short passes.
I've thought about retesting this to see if I would see the same results. While, I tried to keep it even on the number of pass attempts between the two, this could be all random, and I would get a different result if I were to try this again. The other variable I didn't account for is the experience level of my QB (although it was the same QB throwing in both halves, excluding times where the QB had to be replaced with his backup). I do believe that a less experienced QB needs more protection and less receivers to throw to. Whereas a more experienced QB can make more reads, and handle more receivers in the route.
I have a mix of gameplans where I use an extra blocker when I have a FR/SO QB, and then as my QB gets to be an upperclassmen, I start to take the reins off him.
Would be interested to hear other POVs on this.