Yeah, I can explain that. I did defend Castillo. And no, I don't think I was wrong, per se. Here's why.
1. Poor personnel. While I've always been a proponent of gap schemes and I've always been weary of zone, I was hesitant to lay any blame at Castillo's feet exclusively for the simple reason that, for much of his time here, we were hamstrung by poor play on the interior and yes, even at right tackle. We had clear weaknesses at LG, C, and RT for most of Castillo's time with the team, and it's impossible to run inside zone with a bad center. The biggest problem was starting Jeremy Zuttah in an inside zone for two years. Wagner was and continues to be a shit run blocker. That's on John and Ozzie. Now you may ask why I don't blame Castillo for running inside zone when the personnel didn't fit that. I don't think it was Castillo's call. I think it was Marty's and Harbaugh's. It's been clear to me that, under Harbaugh, position coaches focus on technique and coordinators set the overall scheme. By extension, I blame Ozzie, too, for never getting linemen that fit our identity.
2. Every team in the NFL runs the inside zone. Every damn team. A lot of teams run it well. Most of them ran it better than us. I will never blame an OL coach for a run game not working when the scheme is proven to work with nearly every other team. Again, this points to personnel being the issue. To blame Castillo for a scheme not working when that scheme works EVERYWHERE ELSE is fucking stupid.
3. We averaged 4 yards a carry last year. That's not bad. By comparison, we average 4.1 now. Based on the numbers, I'm not sure it's mathematically logical to continue to blame Castillo.
4. Castillo is highly regarded by NFL coaching circles. He's always been considered a top OL coach. Castillo is currently offensive line coach for the Buffalo Bills, who average 129 rush yards a game, good for 6th in the league. McCoy is averaging 4.1 yards per carry and hit 1,000. While with the Eagles, Castillo had a good run game there, too. Castillo's record before and after being with us indicates that he wasn't the problem here.
5. The issues last year, in my opinion, were a lack of runs, an inability to run in short yardage, and an inability to break big runs. These issues can be respectively explained by a pass happy OC; a shitty center, left guard, and right tackle; and the scheme -- inside zone isn't meant to break big runs, and it usually doesn't, unless you have Travis Frederick and Zack Martin.