I really hate excuses. Hate to hear them, loathe to make them, but Marinelli deserves some slack.
Hardy has 40 career sacks over 5 seasons and jus the two double digit sack performances while playing with a dominant D. The year he was suspended he had 1 in the four games he played, and then missed two years of football. I still had high expectations, and think he's a force, but the fact is, he looked gassed at the end of games, became undone mid season, and ultimately was on a team going nowhere fast and his effort seemed to reflect that.
Gregory missed 8 games with his injury and it was one that is known for lingering and hampering players well after the fact. High ankle sprains and hamstring injuries are the most overlooked and misunderstood injuries in sports because they don't require surgery and aren't completely diagnosable. You break a bone and fans will validate it immediately because it appears cut and dry. Bone broke? Can't play (and if you do you're a warrior). Sub par play upon return? It wasn't healed properly the guy just wanted to get back on the field! But sprained ankle or hammy just sound like weak injuries that can be powered through with little effect.
I'm not saying you have to give Rod the benefit of the doubt (I do) but pointing to Hardy and Gregory to say he's no good because they were the premier options is being either obtuse or disingenuous.
All you hear from players is how much they love playing for him, how he gets the most out of them, and that he pushes for effort and responsibility at all times. That's what I hang my hat and opinion of him on. He's had a collection of jags and one semi pro bowl talent who can't stay on the field, with a random bone or two thrown his way over the years and each time he's gotten a toy there was a string attached where he was a head case, a perrenial underachiever, a small school unknown, or other crucial pieces were lost for the season.
Obviously as time goes by it feels like excuse after excuse and he should be running out of them, but outside of last year and really attempting to infuse the D with blue chip talents (addressed above) they've largely given him a scrap heap and said "good luck with all that"