At Stanford, Jim Harbaugh appeared to be the reckoning for the spread offense. His Cardinal offenses promised to bring back power football, with tons of bruising blockers moving around to create a symphony of violence and smashmouth football.

That was what Harbaugh offered to Michigan when he arrived for 2015: to bring back Bo Schembechler-style neanderball and get back to running over opponents.

2018 was Year 4 of the Harbaugh era. In a season-defining showdown with Ohio State, the Wolverines ran 37 times for a solid 177 yards (4.8 per carry) and two TDs. It didn’t stop them from losing 62-39 and seeing their Playoff hopes go up in smoke.

Harbaugh’s last offense at Stanford, 2010’s, finished No. 3 in S&P+. His Wolverines have struggled to put together an offensive line like that one, which yielded six sacks on Andrew Luck all season and produced multiple draft picks. They’ve also cycled through a different starting QB for all four seasons, and they haven’t finished better than 25th in S&P+.

But in 2018, Harbaugh started Michigan down a path that will transform the team in 2019 and beyond. The Wolverines are going to the RPO spread.

Harbaugh made a few substantial changes. They started with hiring run-game guru Ed Warriner as line coach and bringing in Ole Miss transfer QB Shea Pattesron.

Warriner brought a rich background with spread coaches over the last two decades, from Mark Mangino to Urban Meyer to P.J. Fleck. Harbaugh snatched him up to convert Michigan’s power run playbook into a simpler system built around inside zone.

They did exactly that, bumping Shea back into shotgun and pistol alignments so they could run zone-read plays, often from multiple-TE sets. Those sets let them create confusion, pick on different edge defenders, and often give Patterson an escort around the edge:

When defenses were aware enough, they often had their unblocked DE stay home so they could take their chances against the normal Wolverines’ zone running game, rather than give Patterson a chance to dart around the edge. After removing sack yardage (21 for 145 yards), Patterson finished the year with 55 carries for 418 yards at 7.6 YPC, with two rushing TDs. His backup, Dylan McCaffrey, also got in on the act in some of his snaps:

Similar concept, zone read, but with one of the TEs aligned to the other side of the formation before coming back and arcing around the edge for the QB keeper. By reading the Wisconsin outside linebacker, UM got the arcing TE matched up on a CB in the run game, and he drove the corner to the sideline to open up the lane for McCaffrey.

The Wolverines also mixed in a few RPOs for Patterson, but they didn’t make that their full-time approach. They maintained a collection of under-center formations and man and gap blocking run schemes to mix in with their bread and butter, inside zone.

Now, Harbaugh’s brought on Alabama WR coach Josh Gattis to run the offense. Expect the spread evolution to accelerate.

Gattis was a helpful architect of the Alabama RPO spread in 2018, when the Tide had one of the most efficient offenses in history and had defenses ceding all kinds of space.

Michigan’s spring game featured many of Alabama’s staple plays, including this backside slant pass option with some Wolverines personnel twists:

They’re in 21 personnel here, with a TE joining RB/FB hybrid Ben VanSumeren, in addition to a traditional RB. The RB runs a quick flat route to create a slant/flat combination on the backside while the FB is on a path to run outside zone to the other end of the formation.

The goal with RPOs is to make the defense worry about multiple skill players at the same time. This look gives the QB a sort of triple-option trigger that works backwards from pitch to handoff. RPOs work well from the spread but can also work from bigger personnel groups like this one. Essentially, Michigan is running an old-school outside zone play and a West Coast slant/flat route combination, like they might have done any other year. The difference is using a shotgun formation to run both plays at the same time.

No matter how Michigan organizes its personnel packages in real games, mixing in regular RPOs will play to Patterson’s strengths. It will also isolate Michigan’s offensive line against opposing fronts, once defenses back off to stop the quick passes.

Patterson’s first year wasn’t all Michigan could’ve hoped for when it picked him from the wreckage of Ole Miss. His line was a big part of the problem.

It allowed a modest 21 sacks of Patterson, but those included three against both Notre Dame and Ohio State and five against Florida in the Peach Bowl. When the Wolverines faced better defensive ends, their tackles were exposed and their offense had to play with a governor.

The scare with the spread is if Michigan’s tackles can hold up without extra blockers to help. At left tackle, they had to ask John Runyan Jr. to hold things down for them. Runyan is quick, but he was limited by his size at 6’3, 310 pounds. He’ll be back as a redshirt senior and paired with either third-year Andrew Steuber (6’6, 320) or fresheman Jalen Mayfield (6’5, 300) at right tackle. Both are more prototypical tackles, but they’re still green.

But the interior line should be able to maul teams that don’t pack the box with defenders. Center Cesar Ruiz flashed brilliance as a true sophomore in 2018. To Ruiz’s left, he’ll have a fourth-year starter (6’5, 322-pound Ben Bredeson). To Ruiz’s right, he’ll have another massive returning starter (6’3, 350-pound Michael Onwenu). When they’re able to execute double teams on DTs while edge defenders are accounted for with option reads, the Wolverines can pound the ball between the tackles like Harbaugh’s always preferred:

The safety dropping down into the box late made an impressive play to get the tackle there. Without his addition, the Gators were looking at potential catastrophe.

Building around inside zone makes for an easier track to developing consistently good OL at the college level. The rules remain consistent across positions, and players can be moved around more easily to get the best five on the field. That’s a primary reason inside zone is typically the favorite cornerstone of spread run games like Michigan’s building. It poses risks if Michigan’s tackles don’t improve in pass protection, however.

Harbaugh had a unique approach to college offense when he got to Michigan. He was zigging as the sport zagged.

While the sport shifted toward the spread, Harbaugh kept emphasizing under-center formations, fullbacks, and tight ends. The spread approach now is becoming much more uniform and, judging by hires like Gattis, increasingly seen as “best practices.”

Michigan has mostly been able to defeat less-talented teams for years. The question is whether this change makes a difference against Notre Dame or Ohio State.

But there’s reason to be hopeful. If the Wolverines can start to develop tackles more consistently and integrate their skilled hybrids at FB and TE into the RPO game, they can gain an extra gear.