Even with Lacy being in shape in 2014 the Packers used at least two running backs on 41.2% of the team's runs. While that was significantly lower than last season (50.7%) it was still higher than the league average (33.0%).
2014 was a tale of two seasons in this regard. As we recall, Kuhn hardly played in the first half of the season. It wasn't working. Kuhn's snaps went up markedly in those last 7 or 8 games. 2015 was a repeat of that pattern, with Lacy's issues being acute.
The fact that McCarthy went predominantly 1-back through the first half of both seasons waiting for it to jell speaks to preference. As for Lacy's preference, I can only go by what he said. Perhaps he was just being a good soldier in echoing the coach (imagine the kerfuffle if he said otherwise), but I don't think that's the case. The quicker version of Lacy seemed well suited to the single-back zone as a read-and-react style runner in tweener downs and the occasional (or should I say "rare") occasions where McCarthy calls run in a passing down-and-distance.
The key issue in each season was short yardage productivity. Even going back to his rookie season, Lacy's short yardage productivity has been weak. Let's consider the possible reasons.
- First on the list is not having a TE who can run block. Rodgers was outright lousy at it as a rookie, and his second year improvement was marginal at best. It's 3rd. and 1 and you're short handed 1/2 of a lineman. I believe you noted that PFF ranked Cook 11th. in run blocking last season. Having not seen him play last season I'd have to go along with that pending personal observation. While the hope is that Cook can recreate the Finley dynamic, the deciding factor in this signing in weighing his drop history might be his run blocking.
- When going to a 7-man line the TE situation has not been much better. Quarless was a serviceable run blocker at best. At draft time, I expressed a preference for the Packers to look to a run blocking specialist even among the UDFA's. They brought in one (who's name I've forgotten), then cut him in short order. They've since added Pierce Casey who's draft profile indicated some college blocking bona fides. While he may be a long shot, some effort is being made to investigate the issue. It's not like the rest of the backups can be judged more than "just guys". I still like the idea of using Spriggs at TE in short yardage in the absence of other options.
- Rodgers doesn't run many sneaks, despite a good success rate. Over his career, Football outsiders shows Rodgers running 32 times in short yardage, or 4 times per year as a starter, with an 84% success rate. However, in the past 2 seasons, he's attempted only 3 short yardage runs, and for all I know there may have been a broken play among the 3.
Having Lacy and protecting the franchise would be the reasons. However, it's one less thing the defense has to think about in short yardage. It's one of the several small elements that gives this offense the appearance of predictability. Perhaps McCarthy should review how often QBs get knocked out games on sneaks, because in having watched over 50 years of NFL football I can't recall an instance.
- Second to last, but certainly not least, the O-Line is (and should be) recognized as an average run blocking line at best. But when they go off zone blocking to man blocking in short yardage with a targeted hole, they're outside their comfort zone and just don't get much push. Having no TE support compounds the problem.
- Last but not least is something of a speculation: Is Lacy a short yardage runner? We know him to be a punishing guy, but we see that primarily at the second level when he's got up a head of steam. We don't see him plowing his own path to the needed 1 yard. I say this is a speculation because of the above issues...a guy needs some little seam or angle to get leverage on D-Linemen while a LB is coming downhill, and the O-Line doesn't provide much of that in short yardage.
The long and short of it is the preference is for 1-back; that it hasn't worked particularly well in short yardage. The fact that the Packers have left Kuhn behind, a guy who's been highly effective as a lead backer, might suggest a doubling down on that preference in abandoning what has been the late-season security blanket.
